Houston (CNN) Authorities in Texas are working through a steady stream of tips as they seek to track down the "violent, heinous killer" of a 7-year-old girl, Harris County Sheriff Ed Gonzalez said Wednesday.

Gonzalez said none of the tips, including reports there were witnesses to the fatal shooting of Jazmine Barnes, are enough to break the case. When asked by CNN at a news conference whether a tweet that said one witness followed the suspect in his vehicle, Gonzalez said: "I can say that we are receiving tips and we are going through those, but we still have to vet them." He said authorities want to be cautious and prevent the arrest of someone who is innocent. "We want to make sure that we get the right person as quickly as possible," Gonzalez said. In an earlier interview, he told CNN, "We want to make sure we get this violent, heinous killer off our streets." Read More Police have already released a photo of a red truck believed to be involved and a loose description of the suspect. The sheriff said they hope to have a sketch of the gunman, provided by two of Jazmine's sisters, as early as Thursday. For reasons still unknown, the gunman shot into the car driven by her mother and a bullet struck the 7-year-old in the head. The devastating circumstances surrounding the young girl's death have united the Houston area in bewilderment and grief. Authorities are asking for information on who may have been driving this truck. They were on a morning coffee run Jazmine was still in her pajamas Sunday morning when she and her mom, LaPorsha Washington, went on a pre-dawn coffee run to a convenience store. Jazmine and two of her sisters were in the back seat. Dad begs for help finding the gunman who killed his daughter It was about 7 a.m. The family woke up early because Washington's mother was visiting. They were already looking forward to preparing Sunday dinner. But as the family drove near a Walmart, a man in a red or maroon pickup truck pulled up next to their car and started firing, the sheriff's office said. Gonzalez told CNN the truck is a smaller, extended type of pickup and they were still trying to identify its make and model. The gunfire shattered the mother's driver's side window, Washington told CNN affiliate KTRK . She said the truck's driver then sped up to get in front of the family and continued shooting. Washington dived over her eldest child in the front passenger's seat. "I didn't provoke him in any kind of way," the mother said. Gonzalez said the suspect is a bearded white male in his 40s who was driving a red truck. Federal authorities are examining shell casings from the scene. Mom believes race may have played a role Washington said she suspects the attack may have been racially motivated. She said she didn't have tinted windows, and the gunman could see "a black mother with four beautiful children, girls, in this car." Jazmine Barnes was a second-grader at Monahan Elementary School in Houston. The sheriff said the family didn't appear to do anything to incite the truck's driver. "There was nothing to indicate that the family did anything wrong in any way," Gonzalez said. "They were simply just driving along the service road when this happened to them." The sheriff's department is asking anyone who has surveillance video near Wallisville Road and E. Sam Houston Parkway to check their footage for possible clues. The community is horrified Even for officers accustomed to horrific crimes, the tragedy of Jazmine's death has made a profound impact on the law enforcement community. "Help us find this monster before he murders another innocent child," tweeted Joe Gamaldi , president of the Houston Police Officers' Union . "Prayers for Jazmines family, no parent should have to bury a child." Help us identify the person who killed 7-year-old Jazmine Barnes on Sunday. If you live near Wallisville Rd/ E. Sam Houston Pkwy look over your surveillance video. We're looking for a 4-door red truck. If you have info call 713-221-6000 or @CrimeStopHOU at 713-222-TIPS. #HouNews pic.twitter.com/nyMudgs60x

— HCSOTexas (@HCSOTexas) December 31, 2018 Attorney Lee Merritt and social-justice activist Shaun King have announced a $50,000 reward for information leading to the arrest of the gunman who killed Jazmine. And hundreds of donors have contributed to a GoFundMe account to help Jazmine's family pay for funeral expenses. Jazmine's father, Christopher Cevilla, thanked supporters and pleaded for anyone with information to come forward. "I just want anybody, whoever, out there that knows anything about the murder of my daughter, to just please step up as if it was your own," Cevilla told reporters. "Just put yourself in my shoes, in my family's shoes." As for the sheriff, the mission to find Jazmine's killer has gotten personal and he is actively involved in the case. "We're very committed and we're not going to let up. We're extremely upset by this," Gonzalez said.