PHOENIX — A Marana man cannot be executed even though he bludgeoned to death his girlfriend’s two children, the Arizona Supreme Court ruled Tuesday.

In a unanimous decision, the justices pointed out that state law allows someone to be executed only when there are “aggravating circumstances” that make the crime different than other murders. And in this case, prosecutors alleged that the crimes were particularly heinous or depraved.

Prosecutors never established beyond a reasonable doubt that James Granvil Wallace inflicted “gratuitous violence” on the children.

But Justice John Pelander, writing for the court, said that means he has to be sentenced to two consecutive terms of life in prison.

Tuesday's ruling ends any chance Wallace will be executed.

Four years ago the court threw out the death penalty against him for executing his girlfriend. The court ruled then, as now, that there was insufficient evidence to prove an aggravating circumstance.

Wallace confessed to the Feb. 1, 1984, slaying of his girlfriend, Susan Insalaco, 36, and her two children, Anna Monzon, 16, and Gabriel Monzon, 12, in her mobile home near Marana.

Insalaco ordered Wallace to move out because of his alcohol abuse, but instead of leaving he stayed and attacked her children and her one by one as they returned home.

He beat them to death with a baseball bat and a pipe wrench and turned himself in the following morning.