AP

Turkish men pin up a photo of Sarai Sierra, a New York City woman who disappeared while on vacation in Istanbul.

The cellphone of a New York City mom missing in Istanbul has been used twice since she vanished, a Turkish newspaper reported Friday.

Sarai Sierra, 33, hasn’t been seen heard from since Jan. 21, the day before she was supposed to catch a flight home from a two-week vacation.

But police believe the amateur photographer is alive because her phone was used for a Skype call on Wednesday and turned on again Thursday, the Sabah newspaper reported, according to the Turkish daily Hurriyet.

Cops briefly detained a man who exchanged online messages with Sierra after meeting her online four months ago, contacted her while she was in Istanbul and made plans to rendezvous with her on a bridge she wanted to photograph, Hurriyet said.

The man reportedly told police the two never connected, and investigators are now hoping to question three other people she corresponded with on Facebook and Twitter.

Sierra left for her first trip abroad on Jan. 7 — flying solo after a close friend dropped out of the prepaid trip, her family has said.

Her husband, Steven Sierra, said his wife stayed in close contact, talking to him and their children, ages 9 and 11, by phone and Skype.

The last communication from her came Jan. 21, when she sent her sister a brief message saying she would be home the next day.

When she didn't show up at the airport, her husband called her hostel, which said her passport and other personal items were still there.

Police uncovered surveillance-camera footage of Sierra walking around Istanbul during her visit; she appeared to be alone and well.

Steven Sierra and Sarai's brother, David Jimenez, flew to Turkey earlier this week and turned over her online communications to police.

"I don't want to come home without my sister," Jimenez told NBC New York before the trip.

When Coast Guardsman Russell Matthews’ car was found by police abandoned at a Kaena Point parking lot in a remote area of the Hawaiian island of Oahu, the fire department as well as the Coast Guard launched an all-out search.

U.S. Coast Guard

Petty Officer First Class Russell Matthews, 36.

Searchers scoured the north and south shores of the point. The fire department sent out helicopters and the Coast Guard deployed MH-65 Dolphin helicopters of its own. The Coast Guard Cutter Galveston Island, an HC-130 airplane and even a Navy P3 Orion aircraft joined in the effort for the missing 36-year-old man. Some 1,200 square miles of the tropical island and its surrounding waters were searched.

Police told a local TV station the aviation survival technician, a petty officer first class from Air Station Barbers Point, was emotionally distraught. 

On Sunday, the 15-year Coast Guard veteran and father of two showed up at his wife’s Oahu home after nearly four months away. But nobody was home.

Matthews was incoherent and taken to a hospital for observation, Honolulu police said Tuesday, according to The Associated Press. And, as it turns out, Matthews was being investigated for illegal marijuana use at the time of his disappearance, Coast Guard spokesman Chief Warrant Officer Gene Maestas told the Honolulu Star Advertiser.

Military investigators will talk to him when he gets out of the hospital.

Maestas has said the Coast Guard doesn't know where Matthews had been or what he'd been doing since his wife reported him missing Oct. 9, the AP reported. Coast Guard investigators confirmed his identity after he called his command from Castle Medical Center in the Honolulu suburb of Kailua.

He's now being evaluated at Tripler Army Medical Center in Honolulu, according to the AP.

Maestas told the Advertiser that illegal drug use is an offense that could result in a Coast Guard member’s discharge.

Contacted by NBC News on Wednesday, Honolulu police spokesman Capt. Andrew Lum said he could only confirm that Matthews was “no longer a missing person.”

A person in the public affairs office for the Coast Guard in Honolulu said a request by NBC News for information would be forwarded to a superior officer.

AP Photo/DMV via City of Gresham

This DMV photo provided by the City of Gresham, Ore., shows Whitney Heichel.

The cell phone of a missing Oregon woman was recovered Friday, police said, and they hope it will provide clues in the Starbucks barista's disappearance.

Whitney Heichel, 21, was last seen by her husband in a Gresham, Ore. apartment on Tuesday morning, when she left for her work shift to a Starbucks only about five minutes away from her home, police said.

Previous story: Oregon woman, 21, vanished during five-minute commute to work

Gresham Police said Friday they are trying to pull data and fingerprints from Heichel’s cell phone, and called it “a very favorable find,” according to NBC station KGW in Portland. Children playing in a field found the phone and it was turned in to police, KGW reported.

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Authorities are also using dogs to search the area where the phone was found, according to KGW. That is about two miles from where Heichel’s abandoned SUV was found, as well as about a mile-and-a-half from a gas station where her bank card was used the morning she disappeared, KGW also reported. Her vehicle is a black 1999 Ford Explorer with tinted taillights and an Oregon license plate. Police found the SUV with a shattered window, as if someone had rummaged around inside.

Police also said Friday that Heichel’s husband is “not a suspect” in the disappearance, however no one has been cleared in this case, The Oregonian newspaper in Portland, Ore. reported.

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"The longer she is gone, the more this is concerning to us," Gresham police Lt. Claudio Grandjean told reporters Friday morning, according to the newspaper.

Hiechel is 5 feet, 2 inches tall and weighs 120 pounds.

Officials say any information to law enforcement is helpful, The Oregonian reported, and about 50 tips came in overnight. Anyone with information is asked to call the Gresham Police Tip Line.

This article includes reporting from NBC station KGW in Portland and NBC News' Andrew Mach.

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Gresham Police Department

Whitney Heichel, 21, was last seen by her husband at 6:45 a.m. Tuesday before leaving for her shift at Starbucks.

Police in Oregon are investigating the disappearance of a woman who went missing on her way to work Tuesday.

Whitney Heichel, 21, was last seen by her husband at 6:45 a.m. on Tuesday at her Gresham, Ore., apartment before leaving for her shift at Starbucks about five minutes away from her home, police said in a statement.

When Heichel didn’t show up for work, her husband, Clint Heichel, told police he received a call asking if she was sick. He called 911 to report her missing just before 10 a.m.

A team of 24 detectives were following leads and canvassing areas Wednesday where police believe Heichel may have been immediately prior to her disappearance.

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Several transactions were made on Heichel’s debit card the morning she went missing, including once at a gas station at 9:14 a.m. and again at ATM machines and other gas stations at 9:22 a.m. and 9:30 a.m, according to police.

Gresham Police Department

Police said Heichel's vehicle, a black 1999 Ford Explorer with tinted taillights and an Oregon license plate, were found in a Walmart parking lot in Wood Village, Ore., about three miles north of Gresham.

According to a missing person flyer, a gas station attendant at one of the stations said he remembered seeing her SUV and said Heichel was sitting in the passenger seat with a man driving. The man reportedly bought a small amount of gas.

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Heichel’s vehicle, a black 1999 Ford Explorer with tinted taillights and an Oregon license plate, was later found in a Wal-mart parking lot in Wood Village, Ore., about three miles north of Gresham, at 11:17 a.m. The vehicle had a shattered window and it appeared as if someone had rummaged around inside, police said.

Heichel is 5'2'' tall and weighs 120 pounds. Police say they are treating the incident as a suspicious missing persons case. 

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Cook County Sheriff's Department / AP

Daniel Noe went missing in 1978.

CHICAGO — A search for victims of serial killer John Wayne Gacy has led authorities to solve an unrelated cold case – a young man who vanished in 1978 while hitchhiking home to Illinois from Washington state.

Cook County, Ill., Sheriff Thomas Dart said Thursday that Daniel Raymond Noe, then 21, was living in Bellingham, Wash., and working as a surveyor and a factory employee. On Sept. 30, 1978, Noe called his father in Peoria, Ill., to tell him he would return home to complete college at Northwestern University in Evanston, Ill.

Noe was never heard from again.

After reaching out to family and friends and getting no results, Noe’s family filed a missing persons report on Dec. 12, 1978, Dart said.

The sheriff’s office recognized Noe fit the profile of Gacy victims – male, white, 14 to 25 years old, potentially traveling through the north side of Cook County hitchhiking or on a Greyhound bus.

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Gacy was convicted of murdering 33 young men between 1972 and 1978. Gacy was executed in 1994, but authorities kept up the search for victims and last year renewed their efforts, Dart said.

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Detectives took DNA samples from Noe’s parents and sent them to the University of North Texas Center for Identification, looking to see if there was a match with DNA of suspected Gacy victims, he said.

DNA testing didn't provide a link to a Gacy victim, but did match remains found by hikers in 2010 on a steep side of Mount Olympus in Utah, not far from the Interstate 80 that was on Noe’s route home, Dart said.

According to his Bellingham roommate, Larry Wehking, Noe enjoyed mountain camping trips and loved the outdoors, Dart said.

Utah police searched the Mount Olympus area and found no signs of foul play, Dart said.

Dart’s office has solved numerous unrelated, cold missing-person cases and has collected over 40 DNA samples from family members of missing persons fitting the known Gacy victim profiles, the sheriff said.

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"While solving these cases is a bittersweet moment, the Cook County Sheriff's Office is pleased to give families some sort of closure regarding their missing loved ones."

Noe’s family, through his brother, Michael Noe, thanked authorities “for their diligence in locating our loved one after a 34-year absence. Without their help we would not have closure, and Daniel would not be coming home to finally be laid to rest.”

Services for Daniel Noe will be held Monday and Tuesday in Washington and Illinois, Dart said.

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Evan Christian Smith is networking as only an Internet-savvy son with a desperate mission can — to find his father, missing film executive Gavin Smith, who disappeared one week ago seemingly without a trace. 

"plz Help find my Dad. 6'6 220 pounds. Muscular. blond/grey hair. Black mercedes with a surf rack," reads a recent Tweet by the younger Smith, who is a student at University of Southern California.  

The Twitter account and website dedicated to getting out the word and calling for tips have generated an outpouring of interest, support, prayers and retweets, but so far — like the investigation by the Los Angeles County Sheriff's Department — haven't turned up substantial leads in the case. 

Smith, 57, 6-foot-6, 210 pounds — a one-time basketball star at UCLA — was last seen leaving a friend's home in the residential LA suburb of Oak Park on the night of May 1, just a few miles from his home.

Colleagues became alarmed with Smith failed to show up at work. His wife reported him missing by 6 p.m. that evening, according to the San Jose Mercury News. 

His car, a black 2000 Mercedes 420E with padded storage racks on the roof and tinted windows, also remains missing.

The Sheriff's Department issued a missing persons alert on Saturday.

"We really don’t have a whole lot more," said Ray Leyva, a commander in the Sheriff’s Department. "We are still asking the public’s help to find the vehicle and or him."

Investigators are also keeping an eye on the social media posts, Leyva said.

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Smith has worked for 20th Century Fox's movie distribution department for nearly 18 years, according to the company, which put out a statement on his disappearance.

"We are extremely worried about our friend and colleague Gavin Smith and are actively doing what we can to assist the Los Angeles Sheriff's Department in their search for him," the company said.

Family members said the missing man apparently had not used his credit cards since his disappearance and they were unable to contact his cell phone, which seems to be off, Reuters reported.

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