LOS ANGELES -- The union for rank-and-file Los Angeles Police Department officers is urging a state parole board to deny a compassionate release request for the convicted killer of a police officer in the case chronicled in the book and movie "The Onion Field."

The California Department of Corrections and Rehabilitation is considering the case of Gregory Powell. The 77-year-old Powell told the parole board last year that he has terminal prostate cancer.

The Los Angeles Police Protective League said Friday that Powell deserves to die in prison.

Under state law, inmates are eligible for compassionate release if they have six months or less to live. Powell kidnapped officers Ian Campbell and Karl Hettinger during a traffic stop in 1963. He shot Campbell to death in an onion field. Hettinger escaped.