Had the Boston explosions happened a few years ago, the buzz would soon be about the color orange. As in “Code Orange” — the government’s way of indicating a high risk of terrorist attacks under the oft-maligned color-coded Department of Homeland Security terror alert system.

Today, the color chart is history, replaced in 2011 by the National Terrorism Advisory System.

So what should travelers know about the state of airport and mass transit security in the wake of the blasts?

No national alerts have been issued, according to the DHS website. In fact, the agency has never issued an alert under the system, which requires the government to send out “formal, detailed alerts” when it receives information about a specific or credible terrorist threat.

The agency did not respond to an on-the-record request for comment about the process, but in a statement issued Tuesday afternoon, Secretary of Homeland Security Janet Napolitano said there is nothing to suggest at this point that the events in Boston are indicative of a broader plot.

“Out of an abundance of caution, DHS continues to keep in place enhanced security measures at transportation hubs, utilizing measures both seen and unseen,” Napolitano said.

She urged the public to remain vigilant and immediately report any signs of suspicious activity. 

“It is notable that they have not used the (NTAS) system to date,” said Christian Beckner, deputy director of the George Washington University Homeland Security Policy Institute.

“The original color coded Homeland Security Advisory System was so broad that it didn’t lead to effective reactions. This more targeted approach is the right one.”

After the deadly Boston blasts, a number of airports are either beefing up police presence or operating under a “heightened state of alert,” including the three major New York-area airports and Los Angeles International. Airlines are extra vigilant, too, and not taking any chances with suspicious items. On Tuesday, a US Airways flight was remotely parked at Boston Logan International “out of an abundance of caution” so that a bag on board could be examined. The baggage was deemed harmless and the flight taxied to the gate. Airport operations were not impacted.

Related: Reports of suspicious activity spur travel headaches

Regardless of whether or not the government issues a national terror alert, TSA can independently send a security notice to the airlines and recommend additional security measures at airports, Beckner told NBC News.

“That’s more precautionary, not necessarily tied to any specific thing,” he said.

The TSA declined to comment about how the Boston explosions are affecting airport checkpoints, referring all questions to the Department of Homeland Security.

If the government issues an alert under NTAS, it will specify whether there is an “imminent threat” or “elevated threat.” The alert will also explain the potential danger, outline what actions are being taken to keep the public safe, and recommend steps that you can take to protect yourself.

“It’s a vast improvement over the last system,” said Rick Nelson, a senior associate of the Homeland Security and Counterterrorism Program at the Center for Strategic and International Studies.

“I don’t think anybody misses the color coded system except for the late night comedians.”

Each threat alert will have an expiration date so the public doesn’t have to deal with an elevated threat level for an unending period of time, Nelson said. That’s quite a contrast from the previous approach, implemented soon after the 9/11 attacks. Road warriors may remember that the threat level in airports remained at orange for years under the color-coded system.

“It wasn’t really based any credible threat and it really didn’t tell people what to do,” Nelson said. “If I told you the threat level was now red, what did that mean to you as a citizen and what should you do differently? That was always very unclear.”

Five solid tips from people who told authorities that distinctive tattoos helped them recognize a woman seen in photos released Thursday as part of a child molestation investigation led to an arrest in an 11-year-old case involving "widely circulated" child pornography images.

Letha Mae Montemayor, 52, was taken into custody Thursday night outside an apartment complex in North Hills in the San Fernando Valley.

Authorities said they believe the woman is the individual -- identified as "Jane Doe" in a criminal complaint filed Monday -- who appears with an unidentified male in a series of photographs released Thursday afternoon as investigators hunted for leads in the child pornography case.

"Just after ICE’s nationwide plea for public assistance, five separate community tips led to the arrest of Jane Doe," said U.S. Immigration and Customs Enforcement (ICE) Director John Morton. "This arrest would not have happened without the public’s help, and it demonstrates how much individual citizens can do to help law enforcement attack crime."

Also on NBCLosAngeles.com: Second suspect arrested in child porn case, ICE says

An appearance in federal court for Montemayor, charged with one count of making child pornography, was scheduled for Monday.

A neighbor of Montemayor's who did not want to be identified said the suspect was a "hoarder" who "did not take care of her body well" and was "rude to all the children."

About 10 hours before her arrest, Morton and other law enforcement agents conducted a news conference regarding "Operation Sunflower," a recently concluded child sex crimes investigation that led to more than 240 arrests. During the news conference, authorities released images of a man and tattooed woman wanted in connection with a child molestation case authorities said occurred about 11 years ago, possibly in Los Angeles.

"The (tipsters) said they recognized the face, the tattoos," said Homeland Security Investigations Special Agent in Charge Claude Arnold.

"They were very confident that it was she. We expect that it would be more difficult because they were older images, but we were optimistic because they were good images."

ice.gov

These images released by federal authorities as part of a child porn investigation led to the arrest of a woman in Los Angeles.

The woman's tattoos -- a sleeping cat, butterfly and other designs -- are visible in the photographs released Thursday.

123 child victims of Internet sex abuse identified, US officials say

But other clues in the background of the images, discovered by Chicago Homeland Security agents in 2007 and passed along to LA agents, prompted investigators to focus on locations in the San Fernando Valley. Forensics analysis of the images, conducted by the National Center for Missing and Exploited Children, revealed details in the pictures, such as close-ups of the tattoos, a calendar from a store and a phonebook.

The criminal complaint alleges that "Jane Doe," now identified as Montemayor, was involved in the production of child pornography images that were "widely circulated" online. The images depict the sexual molestation of a girl, who appears to be about age 13, according to ICE.

Authorities have not identified the victim or male subject.

"We still want the public’s help in identifying John Doe and the victim in the disturbing series of images that continue to be circulated on the Internet," said U.S. Attorney André Birotte.

Call 866-347-2423 or visit this tips form to provide information. Click here to view the ICE wanted poster.

U.S. Customs and Border Protection / AP file

U.S. Customs and Border Protection agent Nicolas Ivie, 30, who was shot to death early Tuesday near the U.S.-Mexico line in Arizona.

U.S. Customs and Border Protection has identified an agent who was shot to death near Naco, Arizona early Tuesday as 30-year-old Nicolas Ivie, a native of Provo, Utah who has been with the federal agency since 2008, KVOA.com in Tuscon reported.

A news release from Customs and Border Protection said that Ivie and two other agents were responding to a motion sensor that was activated along the border. Another agent, whose name was not released, sustained non-life-threatening injuries and was in stable condition after being airlifted to a local hospital.

The agents who were shot were on patrol with a third agent who was not harmed, George McCubbin, president of the National Border Patrol Council, a union representing about 17,000 border patrol agents, told The Associated Press.

In a statement issued Tuesday CBP Deputy Commissioner David Aquilar said the agency suffered the loss of Ivie "at the hands of criminals operating on the border near Naco, Arizona."

"Agent Ivie died in the line of duty, protecting our nation against those who threaten our way of life," he said. "His death only strengthens our resolve to enforce the rule of law and bring those responsible to justice. Our thoughts and prayers are with Agent Ivie’s family and friends in this difficult time.”

The FBI, which is investigating the shooting with the Cochise County Sheriff's Office, said in a press briefing Tuesday afternoon that they had deployed a special group of agents from Phoenix to process the crime scene.

See coverage at KVAO.com

Authorities did not say whether investigators had recovered guns or bullet casings at the site.

No arrests have been made, but authorities suspect that more than one person fired at the agents.

"It's been a long day for us but it's been longer for no one more than a wife whose husband is not coming home. It's been longer for two children whose father is not coming home, and that is what is going to strengthen our resolve" to find those responsible and enforce the law, said Jeffrey Self, commander of Customs and Border Protection's Arizona joint field command.

The shooting occurred at a patrol base about 100 miles southeast of Tucson named after Brian Terry — a border agent who was killed in December 2010 in an incident at the center of a controversy over a Bureau of Alcohol, Tobacco and Firearms and Explosives (ATF) gun tracking operation known as "Fast and Furious."

Brian A. Terry Border Patrol Station dedicated for slain agent

The operation allowed people suspected of illegally buying guns for others to walk away from gun shops with weapons, rather than be arrested.

Authorities intended to track the guns into Mexico. Two rifles found at the scene of Terry's shooting were bought by a member of the gun-smuggling ring being investigated.

Critics of the operation say any shooting along the border now will raise the specter those illegal weapons are still being used in border violence.

Twenty-six U.S. Border Patrol agents have died in the line of duty since 2002, the AP reported.

Feds reveal more charges in murder tied to 'Fast and Furious'

NBC News' Kari Huus and The Associated Press contributed to this report.

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PORTLAND, Ore. — An Oregon couple were arrested and their two children were rescued after a nationwide search for a "Jane Doe" suspected of child pornography, federal and state officials said Wednesday.

The couple surrendered to Salem police after learning that an acquaintance had identified the wife in "Jane Doe" photos provided to the media by U.S. Immigration and Customs Enforcement’s Homeland Security Investigations (HSI) and shared by the public on social media sites, officials said.

The couple made their initial appearance in federal court Wednesday afternoon on federal child exploitation charges, officials said. NBC News is not naming them to avoid identifying the children.

According to a federal criminal complaint, the couple are accused of producing videos featuring them engaging in sexual contact with two victims who are both under the age of 10 and trading the material for other child pornography.

U.S. Immigration and Customs Enforcement's Homeland Security Investigations

A photo released by U.S. Immigration and Customs Enforcement in seeking the public's help to identify a suspected child pornography producer.

ICE issued the public appeal on Aug. 8.

"When leads turned cold in this case, HSI special agents asked for the public's help," ICE Director John Morton said in a statement. "Thanks to that help, two child victims have been rescued and their accused abusers are in custody. Children have the right to be safe from predators. There is no higher work and we will continue to investigate these crimes with our law enforcement partners."

Watch US News crime videos on NBCNews.com

The images of the child victims were first discovered by HSI Los Angeles in June 2011 during a computer forensics examination of material in a separate child pornography probe, ICE officials said. The material was submitted to the National Center for Missing & Exploited Children's Child Victim Identification Program, they said. The center determined that the child victims had not been identified.

In June, FBI special agents in Denver were conducting an unrelated investigation and found more photos showing the same victims with the woman who was arrested. The center has cataloged more than 200 unique images and two videos depicting the victims.

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ICE

Suzanne Barr, chief of the staff of Homeland Security's Bureau of Immigration and Customs Enforcement.

A top aide to Homeland Security Secretary Janet Napolitano has stepped aside after department officials received new allegations that she made lewd and sexually charged comments to subordinates. 

Suzanne Barr, the chief of the staff of Homeland Security's Bureau of Immigration and Customs Enforcement, has "voluntary placed herself on leave" pending the outcome of a review by Homeland Security's Inspector General and Office of Professional Responsibility, department spokesman Brian Hale said in a statement. 

The move comes a day after lawyers for James Hayes, the director of the ICE office in New York, sent government lawyers sworn affidavits from two ICE officials describing allegedly improper conduct by Barr. 

The affidavits were intended to back up claims Hayes has made in an explosive lawsuit accusing Napolitano and Homeland Security of gender discrimination for ousting him from a top job in Washington and retaliating when he filed a complaint. The affidavits alleged that Barr created a "frat-house type atmosphere" at ICE "that is targeted to humiliate and intimidate male employees." 

In one of the affidavits, which was obtained by NBC News, an ICE official identified as a former assistant attache in Colombia, describes a party at the house of the deputy chief of mission in Bogota during which Barr offered to perform a sexual act on him. In another affidavit, an ICE official describes being present at a meeting in Barr's office in which she made sexually lewd comments about another ICE employee. (The names of the ICE officials who signed the affidavits are blacked out in the versions supplied to NBC News.) 

Hale, the ICE spokesman, last week called Hayes' lawsuit "unfounded." In Wednesday's statement, Hale said about the affidavits, "These allegations are being made in connection with ongoing litigation. ICE will respond directly and strongly to this lawsuit in court as is appropriate."

Homeland Security Secretary Janet Napolitano says the federal government has closed a gap and does review the backgrounds of foreign students who seek to take pilot training at U.S. flight schools.

She added that an American citizen on the no-fly list would not be able to take flight training, contrary to what an administration official said at a Congressional hearing on Wednesday.

Responding to a GAO report out Wednesday that said some number, which was not revealed, of foreign students don't receive background checks, Napolitano told the House Homeland Security committee Thursday that the GAO report was not up to date.

"In 2010, we took steps to be sure all foreign students are vetted. We've been doing it for two years."

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She said GAO faulted Homeland for having no written policy requiring the vetting all foreign students.  Napolitano said that memorandum is being drawn up now but added that the checks have been done even without having the policy in writing.

As for Americans on the no-fly list, Napolitano said they would not be able to take flight training and that officials who testified Wednesday to the contrary "were not aware of all the other things that can occur" that would be prevent them from enrolling.  A Homeland Security official says other checks, that are classified, would stop someone on the no-fly list from being approved for flight training at a U.S. school.

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The Obama administration's announcement Friday that it would defer deporting most young illegal immigrants poses a dilemma for those who are eligible, as they must take a leap of faith that they won't jump to the head of the line for deportation if a future president rescinds the order.

Under the order, the Obama administration wouldn't seek to deport illegal immigrants under 30 who entered the U.S. as children and meet certain other residency and education requirements for the next two years. They also would be eligible to apply for work permits, the Department of Homeland Security said. DHS is the parent agency of the Bureau of Immigration and Customs Enforcement.

The order could apply to as many as 800,000 young illegal immigrants, officials estimated. The Pew Hispanic Center, a project of the Pew Research Center, said later that even more immigrants — as many as 1.4 million children and young adults — could meet the eligibility requirements. That would be about 12 percent of the 11.2 million illegal immigrants estimated to be in the U.S. as of 2010.

But it's not at all certain how many of them will seek to take advantage of the order. That's because it requires eligible immigrants to step forward and ask for the deferment every two years.

Even though President Barack Obama said Friday that the order would "lift the shadow of deportation" over illegal immigrants who were brought to the U.S. while they were children, a future administration could choose to overturn the regulation, jeopardizing those who have identified themselves to the government as illegal immigrants.

A senior administration official, who briefed reporters on the policy Friday on condition of anonymity, conceded that "the executive can always change its mind about how to exercise discretion."

Skepticism, joy among illegal immigrants over Obama decision

NBCLatino: Obama's immigration policy shift sends ripples across the country

For Yelky Ramos, 20, a recent college graduate who came from the Dominican Republic when she was 13, the change means she should be able to get a job.

"We just hope that the way they're going to implement it is going to be fair to the undocumented youth and it won't be a trap, in which people will be applying for this type of deferral and then find themselves … (in) legal proceedings that might lead to deportation," Ramos told msnbc.com. 

Even before Obama appeared in the White House Rose Garden to discuss the order Friday afternoon, Democratic campaign officials were trying to place responsibility for any such "trap" on Republicans, sending reporters "talking points" highlighting previous statements on immigration by Mitt Romney. 

Romney, the presumed Republican presidential nominee, has said he would veto an immigration bill known as the DREAM Act, which would enact many of the policies the White House announced Friday. The measure has passed in the Democratic-led House but has been blocked in the Republican-led Senate.

The memos were meant to get the message out that a vote for Romney — who trails Obama by a significant margin among Latino voters — would be a vote to rescind Friday's order.

DHS Secretary Janet Napolitano told NBC News that there was no immediate danger of applicants' being targeted for deportation, saying the order would be binding for the next two years regardless of who is president. That means Romney, if elected in November, could overturn it as early as 2014, however.

Rep. Charles Gonzalez, D-Texas, chairman of the Congressional Hispanic Caucus, praised Obama on Friday for "taking action to avoid further injustices against young people." 

But "a legislative remedy is still needed," he said.

Until one emerges, illegal immigrants must meet a narrowly specific set of requirements to be eligible for immunity, which DHS outlined in an eight-page document Friday:

• They must be younger than 30.
• They must have been brought to the U.S. before their 16th birthdays.
• They must have been in the country for five continuous years.
• They must have no criminal history.
• They must have graduated from an American high school, earned an equivalent degree or served in the U.S. military.
• They must pass a government background check.

Read the full DHS document (.pdf)

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