SAN RAFAEL, Calif.—The son of a late San Francisco pornography mogul accused of crushing his girlfriend’s skull with a baseball bat will stand trial in her death.

Marin County Judge Kelly Simmons ruled Thursday there was enough evidence to try 27-year-old James Raphael Mitchell, the son of late “Behind the Green Door” director Jim Mitchell, for first-degree murder in the July 12 bludgeoning death of Danielle Keller. The decision followed a preliminary hearing that included testimony from Mitchell’s mother, Mary Jane Grimm.

Grimm, Jim Mitchell’s ex-wife, testified that her son told her he didn’t know his own strength.

Mitchell is also charged with kidnapping the couple’s 1-year-old daughter, who was recovered unharmed.

He has pleaded not guilty. His attorney, Terence Hallinan, says he acted out of passion.