San Quentin State Prison officials released more information this afternoon about Monday’s fatal stabbing of an inmate serving time for killing a Novato girl and maiming her father with his motorcycle in a crosswalk last year. Edward John Schaefer, 44, who had just started serving a sentence of 24 years to life, was in the prison’s reception center yard at about 10:35 a.m. Monday when he was approached from behind by inmate Frank Anthony Souza, San Quentin spokesman Lt. Sam Robinson said. Souza, 31, was serving a life term for killing a homeless man in San Jose in 2007, according to the California Department of Corrections and Rehabilitation. Souza allegedly reached around Schaefer from behind and initially appeared to be punching him in the neck and chest, Robinson said. Souza was actually stabbing Schaefer with a rudimentary knife made from metal found on prison bunk beds and known as a “bone crusher,” Robinson said. The weapon has sharp edges and a point at the end, Robinson said. CDCR spokeswoman Terry Thornton said Schaefer was stabbed several times. He was taken to Marin General Hospital, where he died at 9:03 p.m. Monday, according to the Marin County coroner’s office. There were several other inmates in the “relatively confined” area where the stabbing happened, and San Quentin officials are investigating whether they were involved, Robinson said. Schaefer and Souza were both slated to eventually be transferred to higher security prison facilities, Robinson said. Schaefer had been in the reception center yard for about an hour before he was stabbed, Robinson said. “There were no problems with him so far,” Robinson said. Souza has been in San Quentin since Jan. 12. He has served three previous prison terms totaling seven years and six months since 1998 for grand theft, receiving stolen property and threatening a prosecution witness with force and violence, Thornton said. He was sentenced to 60 years to life for the first-degree murder of John Carl Riggins, 59, in San Jose’s Willow Glen neighborhood on Aug. 29, 2007. Schaefer arrived at San Quentin on July 16 following his sentencing three days earlier for second-degree murder and mayhem. Robinson said he does not know when the two inmates were scheduled to be transferred out of San Quentin. On May 27, 2009, Schaefer drove his Harley Davidson motorcycle at an estimated 55-60 mph in between two cars that had stopped at a crosswalk on San Marin Drive and San Carlos Way in Novato. The motorcycle struck Melody Osheroff, 9, and her 42-year-old father, Aaron Osheroff. Melody Osheroff died the next day at Oakland Children’s hospital. Her father survived, but his right leg had to be amputated below the knee. Schaefer was convicted of vehicular manslaughter, DUI causing bodily injury, DUI with a blood-alcohol level of 0.08 percent or more, second-degree murder and mayhem. Marin County Superior Court Judge Terence Boren sentenced him to 15 years to life for second-degree murder, eight years for mayhem and an additional year for having a prior prison commitment. The judge stayed the sentences on the remaining counts, meaning Schaefer would not have to serve additional time for them unless he violated his parole after his prison release.