The suspect is described as a thinly built white man, possibly in his 30s or 40s, who was wearing a black hooded sweatshirt and looked "sick."
The sketch artist, Lois Gibson, met with Barnes' teen sisters Thursday to give a description of the suspect.
"If we can catch the guy, it's going to help every single thing," Gibson said.
Also, new clearer footage of the suspect's truck was released. The video shows a better picture of the red four-door pickup truck.
Jazmine's mother, LaPorsha Washington, spoke with ABC13 Thursday about her daughter's killer.
"Do the right thing. I know you're hurting just as much as we are hurting because I have strangers, outsiders from all around the world crying every time they see the story. I know you're hurting, so just do the right thing so you can be at peace, too," Washington said.
A Justice for Jazmine rally is planned for Saturday at noon in the parking lot of the Walmart on the East Beltway.
On Tuesday, Jan. 8, a viewing is planned for Jazmine at 10 a.m., followed by a public funeral at noon.
Sheriff releases sketch of suspect in killing of 7-year-old Jazmine Barnes
Celebrities and activists demand justice for 7-year-old murdered in E. Harris Co.
Houston mom says man 'intentionally' killed 7-year-old daughter
Search for clues after 7-year-old shot