The family of a 7-year-old Texas girl shot dead while riding in a car with her mother and three sisters Sunday described the man they say pulled up beside the family's vehicle and opened fire, and authorities released a sketch of suspect later Thursday.

The Harris County Sheriff's Office said the shooting happened on a service road as the family was heading to a store before 7 a.m. Authorities previously said they were searching for a white, bearded man who was driving a red, four-door pickup captured on surveillance video shortly before the shooting in the eastern outskirts of Houston.

Jazmine Barnes died at the scene and her mother, LaPorsha Washington, suffered a gunshot wound to the arm.

This is the man witnesses say murdered 7-year-old Jazmine Barnes on 12/30 as her family drove on the E. Sam Houston Pkwy frontage road at Wallisville Road. Thin white man, 30's-40's, in a red pickup. Call 713-221-6000 or @CrimeStopHOU at 713-222-TIPS #JusticeForJazmine #hounews pic.twitter.com/URR3w2Wxbm — HCSOTexas (@HCSOTexas) January 3, 2019

The family's lawyer Lee Merritt and Harris County Sheriff Ed Gonzalez said after speaking further to witnesses that the man had stubble on his face or a "5 o'clock shadow," but not a full beard. Washington and her 15-year-old daughter Alxis, who was also in the car when Jazmine was fatally shot, described the killer as a white man with blue eyes, a thin build and no beard who was wearing a black hoodie and appeared pale and "sick."

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"The look in his eyes — he wasn't normal," Washington said.

Washington and her eldest daughter met with investigators on Thursday to develop the suspect sketch. Washington said she saw little except for shattered glass and flying bullets. She said her eldest daughter also wasn't able to see much, but would do her best to help investigators.

"That's why I'm so proud of my baby, because after a traumatic thing like that, she shouldn't remember anything — she should block something like that out," Washington said.

Washington's other two daughters, 6 and 13, were also in the car. Washington said witnessing the shooting has deeply affected the children, saying "they can't replace their sister." Alxis, her eldest daughter, said Jazmine was bossy and liked to eat. She said she would miss her "beautiful smile."

Authorities are searching for a red pickup truck, left, in connection with the fatal shooting of 7-year-old Jazmine Barnes, right, Sunday near Houston KHOU

Washington said Jazmine had told her she wanted to be a teacher.

"We're missing a piece of our puzzle," Washington said.

Washington said she doesn't believe the shooting was a case of mistaken identity. She said the man drove around from the passenger's side of the vehicle to the driver's side and was able to look inside the vehicle because it didn't have tinted windows. She said he must have known there was a woman and three children inside. Washington, who is black, said she believes the shooting may have been a hate crime.

Gonzalez, the sheriff, said Wednesday that the investigation is focused on collecting evidence and developing leads, and investigators haven't yet determined a motive.

"We're not tone deaf to some of the concerns in our community where this could be potentially race-related," Gonzalez said, explaining that road rage could be another consideration. But he added he doesn't want speculation on a possible motive to limit the scope of an investigation that has one primary aim: finding the shooter.

"It's a whodunit right now," Gonzalez said.

The sheriff added that investigators are "not ruling anything out."

Washington thanked the community for an outpouring of support. Houston Texans' wide receiver DeAndre Hopkins and basketball legend Shaquille O'Neal have both reportedly offered to donate to the child's funeral, which is planned for Tuesday. Activist Shaun King and Merritt, the family's lawyer, have also raised $100,000 as a reward for information that leads to the killer's arrest.

Washington said she believed the killer would eventually turn himself in.

Family of Jazmine Barnes gives new description of her killer https://t.co/y8DTZImvoE pic.twitter.com/yMR1xMhALv — KHOU 11 News Houston (@KHOU) January 3, 2019

"It's not going to be no amount of money, it's going to have to be him," Washington said. "His heart is finally going to get to him, his conscience is finally going to get to him after seeing my child's face go across this TV so many times."

Houston activists on Wednesday held a news conference, saying they believed the attack was racially motivated and pointed to an unsolved incident in the area in 2017 in which a suspect described as white shot into a vehicle carrying at least two black people.

Do you recognize this truck? This is the truck of the suspect who fatally shot 7-year-old #JazmineBarnes. If you have any information call 713-221-6000 or @CrimeStopHOU at 713-222-TIPS. #HouNews #JusticeForJazmine pic.twitter.com/8IKFb4SJ3S — HCSOTexas (@HCSOTexas) January 3, 2019

"Black people are being targeted in this country. Black people are being targeted in this county. Black people are being targeted in this city," activist Deric Muhammad said. "So we are thoroughly convinced that the killing of Jazmine Barnes was race-related."

Gonzalez said his office is revisiting the 2017 case as part of the investigation into Jazmine's death. He has described Sunday's shooting as "totally unprovoked" and asked people who live nearby to review their surveillance videos.

Jazmine's father, Christopher Cevilla, said his daughter was a loving and caring girl who was "very smart in school."

"Justice will prevail, and I will be leading the charge," Cevilla told reporters Thursday. "He's going to slip up somewhere, and I'm going to be there. He's going down for sure."