MARTINEZ -- A suspected gang member was arraigned on murder charges Wednesday for allegedly killing a Brentwood man outside a Concord party last weekend.

Prosecutors say 29-year-old Vincent Ochoa, of Concord, fatally shot 25-year-old Ismael Garcia Ramirez in the head Saturday night in the parking lot of a Mi Casa Court apartment building. Ramirez was at the building for a large family party thrown in honor of a relative's baptism.

Investigators are still working to determine a motive but suspect that Ramirez may have been targeted because he had gotten into an argument with one of Ochoa's gang associates at the party, a prosecutor said.

Ochoa was charged Wednesday with murder with use of a gun, and a charge enhancement alleging the killing was committed for the benefit of a criminal street gang. He returns to court April 17 to enter a plea to the charges.

Ochoa is being held in County Jail in lieu of $2.3 million bail.

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.