HOLLYWOOD, Fla. -

The mother of a teenager murdered in July hopes an $8,000 reward helps police catch his killer.

"I didn't want it to go this far," said Jacob Rivera's mother, Sara Crosthwaite. "I'm not giving up. Every day I do whatever I can to help."

Rivera, 16, was shot while walking along Johnson Street on July 12. He died three days later.

Surveillance cameras captured the gunman -- who covered his face with a white shirt -- as he ran up to Rivera, shot him in the head, then ran away.

"He was just a young boy, just turning 16," said Crosthwaite.

Broward Crime Stoppers will feature Rivera on its mobile billboard in the coming weeks, driving it around the area where he was killed and touting the now $8,000 reward for information leading to an arrest.

Hollywood police haven't released much about a possible motive. Crosthwaite acknowledged her son was more interested in gang life than schoolwork, but said he was trying to turn his life around.

"It doesn't matter what he did or what he was involved in," she said. "This person took a 16-year-old's life and that easy, he can take anybody else's life out there."

Anyone with information on the murder is asked to call Broward Crime Stoppers at 954-493-TIPS. Crime Stoppers is providing $3,000 of the reward. A friend of the Rivera family is providing the other $5,000.