Convicted murderer James Lee Crummel – on California’s death row since 2004 – has committed suicide, the Department of Corrections and Rehabilitations said Tuesday.

Crummel, 68, hung himself in his San Quentin State Prison cell. He had been convicted in the 1979 kidnapping, sexual abuse and killing of 13-year-old James Wilfred Trotter.

According to the CDRC, there have been 20 death row inmates who have committed suicide since 1978. Only 13 people have been executed by the State since 1976; there are 723 people currently on death row.

Another 57 have died of natural causes. The last person in California to be executed by the state was convicted murder Clarence Ray Allen back on January 17, 2006.

A Federal court moratorium on carrying out executions has been in place since 2006, due to concerns on whether the lethal injection method carried out in California constituted cruel and unusual punishment.