A University of California, Irvine graduate student has been charged with gunning down his ex-wife while she picked up the couple's 4-year-old son.

The Orange County district attorney's office filed the charge Tuesday in a Newport Beach court against 35-year-old Brian Benedict. He faces 50 years to life if convicted.

Benedict is a physics graduate student who lives on campus. Prosecutors contend that he swung a hammer at 30-year-old Rebecca Benedict when she went to pick up their son after a visit Sunday night, then chased and shot her.

The boy wasn't harmed.

Court records show Brian Benedict was recently ordered to pay twice as much child support as he had expected.