Police have released a sketch of the man they believe killed a seven-year-old Houston girl who was shot dead in her family's car this week.

Jazmine Barnes was in the back seat of her family's car with her three siblings and mother when the driver of a red pickup truck pulled alongside the vehicle and fired inside, killing her on Sunday December 30.

The Harris County Sheriff's Office has released the sketch of the suspect based on descriptions by Jazmine's family.

The suspect is a white man with pale skin, blue eyes, a thin build and a mustache and is believed to be in his 30s or 40s. He was wearing a black hoodie at the time of the shooting.

The Harris County Sheriff's Office released a sketch of the man (left) who shot dead Jazmine Barnes, seven, (right) on Sunday morning in Houston, Texas

She was in the backseat with her mom and three sisters stopped at a red light near a Walmart when the driver in a red pickup truck pulled up and opened fire

Sheriff Ed Gonzalez said in a press conference on Thursday that the suspect could have changed his facial hair by now.

Jazmine's mother LaPorsha Washington said the gunman looked 'sick'.

Cops also released a short surveillance video from a nearby business of the killer in his red pickup truck shortly before the shooting, asking for people who recognize the vehicle to come forward.

A reward of 100,000 has been set for any leads to the killer.

Jazmine's tragic death has caught national attention leading activists like Shaun King and celebrities like Gabrielle Union and Olivia Wilde to rally for her killer to be found.

The shooting unfolded as Jazmine, her mom, and three sisters - two teenagers and one six-year-old - were traveling through North Houston around 6.50am to get coffee, according to Abc13.

The family was stopped at a red light near a Walmart at the time of the shooting.

The suspect who killed Jazmine is a white man with blue eyes, a thin build and a mustache and is believed to be in his 30s or 40s. He was wearing a black hoodie at the time of the shooting

Jazmine's tragic death has caught national attention leading activists like Shaun King and celebrities like Gabrielle Union and Olivia Wilde to rally for her killer to be found. Jazmine is pictured with father Christopher Cevilla

Cops released this photo of the shooter's red pickup truck shortly before the shooting

The driver pulled up to Jazmine's family's car and opened fire, shattering the driver's side window, according to the New York Daily News.

Jazmine died at the scene. Her mother suffered a gunshot to the arm and her six-year-old daughter was also wounded in the shooting.

Houston activists earlier 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.

Authorities said they are investigating the possibility of a hate crime and the 2017 case. Investigators are comparing the shell casings from the shooting to other cases to see if there are any connections.

'We are not going to rest until we have justice for Jazmine. We’re continuing to proceed with different strategies to try to find this coward of a killer, this person that does not need to be on our streets,' Sheriff Ed Gonzalez said.

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

The shooter pulled alongside the mother's car (pictured) and fired into it, killing the girl. The mother managed to flee the scene in her car and came to rest on a highway median

'We will not rest until we solve this case,' Harris County Sheriff Ed Gonzalez told reporters on Wednesday. 'It’s not easy. We need help, but I’m confident we’re heading in the right direction.'

The heartbroken mother spoke to reporters from her hospital bed pleading for help in finding the killer.

'He intentionally killed my child for no reason,' she said through tears.

Jazmine's sister Alexis Dilbert, who was in the car, told ABC she was able to see the suspect's face during the shooting.

'You know when you're driving and you look in someone's car and you make eye contact? It was like that,' she said.

Jazmine's family believes her death was a deliberate hate crime.

They said the gunman deliberately looked inside both sides of the car before firing inside, attorney Lee Merritt said on Thursday.

He pulled up to the passenger side of the car, then came around to the driver's side and observed all the girls inside, according to Merritt.

'We didn't do anything wrong to this man. It was something in his mind that he had planned on doing beforehand. This is something that I believe was a hate crime,' Jazmine's mother Washington said.

Jazmine would have turned eight years old next month.

A Justice for Jazmine rally is planned for this Saturday in the parking lot of the Walmart near where she lost her life.

On Tuesday January 8, a viewing is planned followed by a public funeral at noon.

If you have any information about the shooting, call the Harris County Sheriff's Office or Crime Stoppers at 713-221-6000 or 713-222-TIPS.