Two San Quentin death row inmates died of natural causes over the weekend, state corrections officials said today. Fred Harlan Freeman, 69, and Miguel Angel Martinez, 39, both died while being treated at community hospitals in Marin County for long-term illnesses, San Quentin spokesman Lt. Rudy Luna said. Freeman had been on death row since 1987 after being convicted in Alameda County of first-degree murder committed during the robbery of a Berkeley bar in 1984. Freeman and two others had robbed bar patrons, and during the robbery Freeman shot Donald Koger in the head, killing him. Freeman died on Saturday, Luna said. Martinez had been on death row since being sentenced in Los Angeles County Superior Court in 1998 for killing a man during a home robbery. He died on Sunday, Luna said. Since California reinstated the death penalty in 1978, 47 death row inmates have died of natural causes, according to the Department of Corrections and Rehabilitation. Seventeen have committed suicide, 13 have been executed in California and five have died from other causes, including killings by other inmates.