YNOT – A California judge on Thursday ruled enough evidence exists to try James Raphael “Rafe” Mitchell, son of late San Francisco porn pioneer Jim Mitchell, on first-degree murder charges in the bludgeoning death of his former live-in girlfriend.At least part of the judge’s decision was predicated on testimony from Rafe Mitchell’s mother. Mary Jane Grimm, Jim Mitchell’s ex-wife, told the court her son said he “didn’t know his own strength.”

In late July, Mitchell, 27, pleaded not guilty to charges he used a baseball bat to crush the skull of 29-year-old Danielle Keller, whose body was found July 12 in the backyard of the Novato, Calif., home she shared with her mother and the daughter Rafe Mitchell fathered. Mitchell also is charged with abducting the child, who was recovered unharmed hours after the murder. Samantha Mitchell celebrated her first birthday the day her mother was killed.

According to a statement from the victim’s mother, Keller and Mitchell became estranged after the birth of their daughter. Keller’s mother, Claudia Stevens, told the San Francisco Chronicle “a series of frightening events” resulted in the issuance of a restraining order against Mitchell earlier this year. Keller had sole custody of the child.

Mitchell’s attorney, Terence Hallinan, has characterized the killing as a crime of passion.

July 12 also marked the second anniversary of the death of Rafe Mitchell’s father, who in 1969 co-founded an infamous San Francisco porn empire before shooting to death his brother and longtime business partner in 1991. Jim Mitchell served three years in prison for manslaughter after kicking down the door of Artie Mitchell’s home during what he claimed was an attempt to intervene in Artie Mitchell’s drug and alcohol abuse.

The brothers not only founded the Mitchell Brothers O’Farrell Theatre, but also lensed landmark works of adult cinema. Behind the Green Door, the movie that killed the late Marilyn Chambers’ hopes for mainstream acting and modeling careers, was an early hit for them.