Norwalk~A La Mirada man pleaded no contest today to vehicular manslaughter in a fatal hit-and-run last September that killed a 72-year-old man, the District Attorney’s Office announced.

Geoffrey Matthew Rocha, 27, also admitted an allegation that he fled the scene of the Sept. 20, 2011 accident that killed Raul Quintanilla, said Deputy District Attorney Marlon Powers.

Rocha is facing seven years in state prison when he returns Aug. 22 for sentencing before Commissioner Michael Schuur in Norwalk Superior Court.

Rocha pleaded no contest to striking Quintanilla, who was out for his daily walk, at the intersection of Santa Gertrudes Avenue and Lawnhill Drive in La Mirada.

Authorities said the victim’s arm was severed at the shoulder with the force of the impact and carried away by the fleeing car. The limb was discovered about a mile from where the victim was struck.

The defendant, who fled the scene of the 4:30 a.m. accident, later surrendered to Los Angeles County Sheriff’s Department authorities in Norwalk.

In exchange for his plea, prosecutors will ask that the remaining two counts-leaving the scene of an accident and driving when privilege suspended-be dismissed at sentencing.