The mother and aunt of a teenager charged in the death of a Georgia baby were arrested Tuesday for allegedly lying to investigators, police said.

The arrests came the morning after 17-year-old De'Marquise Elkins' first court appearance on murder charges in connection with the fatal shooting of 13-month-old Antonio Santiago. Santiago was in a stroller on a walk with his mother, Sherry West, in the coastal town of Brunswick on Thursday when the shooting occurred. West was also shot.

Karimah Aisha Elkins, 36, and Katrina Latrelle Elkins, 33, were booked on charges of making false statements to police and concealing facts or providing fraudulent documents in matters of government, Glynn County police said.

According to FirstCoastNews.com in Georgia, Karimah Elkins is De'Marquise's mother; Katrina Elkins is his aunt. The station said the pair was arrested at 6:40 a.m. on Tuesday. Karimah Elkins posted bond of $1,104 at about 8 a.m., but Katrina Elkins was held in custody for a probation violation hold in neighboring Henry County.

De’Marquise Elkins and 15-year-old Dominique Lang, are both charged as adults in the fatal shooting, which West told police started when the two suspects demanded money. When West told them she didn't have any cash on her, she said the older teen, Elkins, pointed a handgun at her.

Glynn County Police Department

De'Marquise Elkins, age 17.

"He says, 'Well, I'm gonna kill your baby,'" West said last week. "I put my arms over my baby and he shoves me. And then he shot my baby right in the head."

West, the only eyewitness to the shooting, also received a non-life-threatening gunshot wound to the leg, police said.

Elkins' aunt told FirstCoastNews.com over the weekend that she was with her nephew on the morning of the shooting, which happened at about 9 a.m.

"Marquise was with me. At 8 o'clock that morning. At 8:15, De'Marquise, was at my residence," she told the station, adding that she was with him until about 11:30 a.m. "At 12 o'clock, Marquise was signed into adult education. He was not at that crime scene. How can he be two places at one time?  That's not true. There ain't no way."

A few hours later, she said, she picked him up. "It was a normal day. He wasn't nervous or nothing."

West says she picked the gunman out of a photo lineup of 24 mugshots, and insists Elkins is the killer.

Before Elkins' first court appearance on Monday, public defender Kevin Gough, who represents him, told The Associated Press, "My client is absolutely, 1,000-percent not guilty."

Elkins did not enter a plea.

Lang, the other suspect, was in eighth grade before his arrest, The Associated Press reported. His grandmother told WJXT-TV in Jacksonville, Fla., that Lang doesn't even know Elkins and could not have been a part of a killing of a child.

"My grandbaby ain't like that. He a baby, but he's not a baby killer," Verdell Hunter told WJXT-TV. "So they need to get that straight. He's not a baby killer."

Terry Dickson / The Morning News via AP

Authorities investigate the scene of shooting in Brunswick, Ga., on Thursday.

Two teenage suspects were arrested in a small coastal Georgia city a day after a baby was killed and his mom shot, authorities said Friday.

The mother, Sherry West, told FOX affiliate WAWS-TV that she was pushing her 13-month-old son, Antonio, in his stroller in Brunswick, Ga., Thursday morning, when two boys – described as about 10 and 15 years old – came up, demanded money and shot them.

Brunswick police announced Friday afternoon that they had arrested a 17-year-old and a 14-year-old, and that they were charging them with murder. The arrests came after SWAT teams had gone door to door, searching for clues, and police had checked local school attendance and absentee lists to see if there were any students who hadn't been at school that fit the description of the suspects.

West told WAWS-TV that the older boy pointed a handgun at her during the encounter Thursday.

"He said, 'I'm gonna kill you if you don't give me your money,' and I said, 'I swear I don't have any,'" she told WAWS-TV of the encounter. 

She said they wouldn't accept no for an answer.

"He says, 'Well, I'm gonna kill your baby,'" she told WAWS-TV, crying. "I put my arms over my baby and he shoves me. And then he shot my baby right in the head." 

Glynn County Police Department

De'Marquise Kareem Elkins, 17.

West was shot in the leg, according to local reports. Brunswick police spokesman Todd Rhodes confirmed she received a non-life-threatening gunshot wound from a handgun.

Brunswick police identified the 17-year-old suspect as De'Marquise Kareem Elkins. The 14-year-old's identity, since he is a juvenile, was not made public; under Georgia law, 17 is considered an adult.

West was the only eyewitness to the crime, Rhodes said. Residents in the area reported hearing gunshots, but didn't see anything, he said. 

"We're not leaving any stone unturned," he said earlier in the day.

In a news conference Friday afternoon, Brunswick police chief Tobe Brown said, "We're still following leads from our witnesses. We're still collecting evidence. ... We're currently serving search warrants at three locations within the city." 

Police hadn't located a weapon yet.

The baby's father, Louis Santiago, said to WAWS-TV, "Why? Why my little one? You know? You feel they could have just taken the pocketbook and go."

Brunswick is about 80 miles south of Savannah.

This story was originally published on Fri Mar 22, 2013 9:56 AM EDT