Updated

Federal prosecutors and defense attorneys for convicted killer John McCluskey are scheduled to deliver closing arguments Monday in the first phase of his sentencing trial.

It's up to jurors whether the death penalty will be an option as they decide McCluskey's punishment for the slayings of an Oklahoma couple.

McCluskey was convicted Oct. 7 in the August 2010 carjack killings of Linda and Gary Haas of Tecumseh, Okla., following his escape from an Arizona prison.

Defense attorneys have tried to spare McCluskey from the possibility of execution. They say he's incapable of controlling his impulses due to brain abnormalities, emotional and physical abuse, and a long history of drug and alcohol abuse.

A neurologist who testified last week for the prosecution said McCluskey was capable of controlling himself.