MANTECA, Calif. -- Two cities in the Central Valley are trying to figure out how to deal with gang violence.

Manteca police said half of the city's homicides and aggravated assaults are because of gang violence.

Roberto Ramirez, 14, was shot and killed Tuesday along a Stockton sidewalk.

On the same day in Manteca, a car pulled up to a man who officials said is a documented gang member. Five shots were fired, and he was wounded in the chest.

Recently, Manteca police seized more than 24 guns including assault rifles. Authorities said it was one gang's arsenal.

"The ability for somebody to drive by at 45 mph and spray a neighborhood with an AK-47 rifle gives that gang a lot of power," Manteca police Capt. David Bricker said.

Last month in Stockton, two adults and two juveniles were charged in the shooting death of an innocent bystander, 13-year-old Aaron Kelly.

"It's not fair that my son or anyone else's son having to be killed over stupidity," Renee Garcia, Kelly’s mother, said.

Stockton police have a tip line that offers rewards on guns used in crimes.

Anyone with information on gangs should call 209-937-GUNS. Callers can stay anonymous.