SANTA ANA - An Orange County teenager who was 12 years old when a gang rival was shot to death has been convicted of first-degree murder.

The now-14-year-old boy was backing up his buddies in the 2006 retaliation killing of 23-year-old San Chea. He may be the county's youngest-ever convicted murderer.

Juvenile Court Judge Joy Markman convicted him Wednesday. Although the defendant didn't pull the trigger, he was found guilty because he was part of the killing conspiracy.

The teen could be placed in custody until age 25 when he's sentenced Oct. 6.