He was wearing a black hoodie at the time of the shooting.
During a news conference Thursday afternoon, Sheriff Ed Gonzalez expressed condolences to the family as some of the latest details in the case were released to journalists.
Also on Thursday, investigators released new surveillance video of the pickup in question.
Services for Jazmine will begin at 10 a.m. Tuesday with a viewing at Green House International Church, followed by her funeral at noon.
Merritt also said the shooting bore similarities to an August 2017 attack on a black man and woman - this one involving a silver pickup.
A $100,000 reward is now available for anyone who has credible information, which will lead to the arrest of the white man who shot and killed 7-year-old Jazmine Barnes. First, he pulled up to the passenger side of the auto, then came around to the driver's side, which gave him the opportunity to observe all of the young girls inside, Merritt said. Jazmine died at the scene while her mother was shot in the arm.
On Sunday, an unknown gunman shot into a vehicle driven by Barnes's mother, LaPorsha Washington, striking the 7-year-old girl in the head.
No racial slurs were said during the attack, but Merritt said they still believe the shooting was racially motivated for a "litany" of reasons, including the area where it took place and the racial rhetoric now dividing the nation.
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The two parts will be voted on separately on the House floor on Thursday, said Democrats, who will hold a 36-seat majority. The second bill would reopen and fund the Department of Homeland Security (DHS) only on a short-term basis.
Gonzalez said authorities have not yet determined a motive in Sunday's shooting and have not found links between it and the 2017 cases.
The shooting remains under investigation.
"We're not going to rest until there is justice for Jazmine", Gonzalez said. She said she initially heard shots fired from a vehicle behind her, and then the driver pulled in front of her auto and slowed down as he continued to shoot at them.
Sometimes they call him a loner or tormented soul in need of help - I say call them what they are, domestic terrorists. I am joining the search for her killer and have a $25,000 reward. "He intentionally killed my child for no reason". "He didn't even know her, he didn't know who she was".
"When she said Jazmine the third time, I turned the light on in the auto and turned around and looked at my baby", Washington said. It was like that, ' she said.
The killing of the seven-year-old has drawn national attention, including that of celebrities.
Civil rights attorney Lee Merritt, who represents Barnes' family, also spoke at the briefing and described how witnesses talked with police "after some reflection" and helped provide more details about the suspect and what went down.