Johnson was found guilty of first-degree murder on Tuesday for the killing of Gary DeBartolo and Sandy DeBartolo.
Investigators said the DeBartolos were killed in cold blood when Johnson and five others tried to steal marijuana from the couple's Kerman home.
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It wasn't immediately clear when Johnson would face sentencing, but he could face the death penalty for the crime.
The five other defendants have already been convicted in the murder case.
Johnson was also charged with attempted murder, robbery, and mayhem for a separate robbery and brutal attack in Fresno that occurred a few days before the DeBartolos' murder.
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