A jury has deadlocked on whether a once-respected fire captain should receive the death penalty for setting a 1984 fire that killed four people in a case virtually spelled out in his manuscript.

After the jury said it was deadlocked 8-4 in favor of executing John Orr, Superior Court Judge Robert Perry declared a mistrial in the penalty phase of the case Thursday. He scheduled sentencing for Sept. 17.Prosecutors must decide before then whether to retry the penalty phase with a new jury. If they decline, Orr will be sentenced to life in prison without parole.

Orr, 49, was convicted June 27 of four counts of first-degree murder for igniting a blaze in a South Pasadena hardware store and 20 counts of arson for a series of brush fires that destroyed dozens of homes.