BRUNSWICK, Ga. -

A bullet recovered at the crime scene where a 1-year-old boy was killed will be tested ballistically against a .22-caliber handgun found in a pond two miles away, Glynn County Police Chief Matt Doering said at a news conference Thursday afternoon.

This comes a day after a Georgia grand jury indicted 17-year-old De'Marquise Elkins in last week's fatal shooting of 13-month-old Antonio Santiago in his stroller and in another unrelated shooting 10 days earlier in a robbery attempt.

The indictment says Elkins shot the boy in the face with a .22-caliber revolver while trying to rob the child's mother.

Doering said Thursday investigators found one bullet in Santiago's body, it's now at the crime lab, along with the gun police believe was used in the crime.

"Our investigators, as we speak, are still out interviewing people," Doering said. "There was more evidence recovered last night. There is still evidence we know that we are still searching for."

The indictment charges 15-year-old Dominique Lang on seven counts including felony murder. Elkins' mother, 36-year-old Karimah Elkins, and sister, 19-year-old Sabrina Elkins, were charged with trying to dispose of the gun in a saltwater pond.

DOCUMENT: Read the full indictment of 5 in killing of toddler

"We know who, we know when, we know where and we know how the firearm was hidden transported and disposed of," Doering said.

Doering said there was a vehicle involved in transporting the gun, and he said investigators know who it belonged to, but wouldn't say who.

Karimah, Katrina and Sabrina Elkins

(Karimah, Katrina and Sabrina Elkins pictured, right)

The gun recovered Tuesday was found in a pond in a gated subdivision behind Brunswick Floors on U.S. Highway 17, just more than two miles from the shootings, Doering said.

Investigators were tipped off to the location of the gun after investigating Karimah Elkins and her 33-year-old sister Katrina Elkins. Police arrested and charged the two women with lying to police about who was with DeMarquise the morning Santiago was killed.

The lawyer representing Lang also spoke Thursday. Kimberly Copeland wants to make it clear that her client, she believes, had no part in the heinous crime.

She said he did not know the other teen accused of the shooting and was merely a witness who's being wrongly held.

13-month-old Antonio Santiago

"I believe full-heartedly in my client's innocence, and I am going to represent him fiercely on these charges," Copeland said. "I don't think that he should be listed as a co-defendant."

Copeland said Lang never even knew De'Marquise Elkins, and she said he surely wasn't his friend.

"They're not in school together," she said. "There's a substantial age difference between the first defendant and my client. There's no relationship."

Copeland was hired by Lang's family on Tuesday and said she wants to keep most of what she knows out of the media and in the courtroom. She does admit that her client wasn't at school last Thursday when the shooting happened. Instead, she said, he was out sick.

"Normally he would have been in school," Copeland said.

She said Lang did see the crime take place, but had nothing to do with it, despite what many people have said. She would not go into detail, just said he was only an eyewitness.

"That's the only role he would have," Copeland said. "He didn't participate. He didn't approach. He did not request anything from the victim. He did not shoot anyone. So he didn't participate."

Copeland said she's filing several motions to get the charges against her client dropped.