Brunswick, Georgia (CNN) -- The sister of De'Marquise Elkins, one of the two teenage boys accused of fatally shooting a 13-month-old baby in Brunswick, Georgia, has been arrested on an evidence tampering charge, the Glynn County Sheriff's Office said Thursday.
Sabrina Elkins, 19, was named in a grand jury indictment released Wednesday, accused of helping her mother get rid of the gun authorities say was used to kill the child during an attempted robbery on March 21.
Authorities did not reveal her alleged role in disposing of the gun, which police found in a pond 2.3 miles from where 13-month-old Antonio Santiago died.
"She was part of that, and that's the most I can answer of that question right now," Glynn County police Chief Matt Doering said.
The grand jury also indicted Elkins' mother, Karimah Aisha Elkins, 36, and aunt, Katrina Latrelle Elkins, 33, on charges of making false statements or writings, among other things. They had been arrested earlier.
None of the women are accused of involvement in the actual shooting. Police say their relative, De'Marquise Elkins, 17, and another boy, 15-year-old Dominique Lang, were.
The same grand jury that indicted the women also accused De'Marquise Elkins and Lang in the shooting, prosecutors announced Wednesday. Elkins is accused of malice and felony murder, along with other charges. Lang is accused of felony murder.
CNN is identifying Lang because he is charged as an adult and media in the community have been naming him since he was arrested.
Investigators are looking into the possibility of a gang tie to the shooting, Doering told reporters Thursday.
"That's being explored, whether a gang involvement was part of this. And that's all that I can say right now," he said.
He declined to say whether more arrests were possible. He said investigators remain in the field, working leads and searching for evidence.
The shooting occurred on March 21 while the baby's mother, Sherry West, was walking her son in a stroller. Two teenagers approached her, and one pointed a gun and demanded money, she said.
The boy with the gun said, " 'Give me your money or I'm going to kill you and I'm going to shoot your baby and kill your baby,' " West said.
She said the boy tried to grab her purse and opened fire when she told him she had no money. He then shot at her -- hitting her in the leg and grazing her head -- then shot the baby in the face, she said.
West tried in vain to resuscitate her son as bystanders called 911 for help.
Sabrina Elkins, who is being held without bond, will appear before a magistrate at the Glynn County Detention Center on Friday, said April Smith, deputy clerk at the Glynn County Magistrate Court.
Victor Blackwell reported from Brunswick, Georgia; Michael Pearson reported and wrote from Atlanta; and CNN's Chris Youda contributed to this report.