Cops say maintenance man Anthony Stiger and his wife Melanie Constantini, both 20, murdered Harold Myles Shilberg, before abandoning their apartment and going on the run.
Investigators found a bloody electric saw and clothing at the crime scene in their Las Vegas apartment.
Cops said the couple was videotaped at a rental store in Las Vegas buying a garment-sized box like the one in which Shilberg was found.
Stiger denied the couple were cold blooded killers and has instead claimed that Shilberg was killed in self defense.
He told KTNV: "I'm not going to sit here and say I take full responsibility for it, because he's a grown man just like I am.
"When he grabbed the saw, I grabbed it back. I got the opposite end of the saw. I grabbed the saw and basically was fighting for my life in the sense of trying to get him not to cut me."
He added that he wasn't for running away, but he had been encouraged to get his two-year-old away from the grisly scene by his grandparents, who own the apartment complex.
He said: "It wasn't about running. The only reason why I left was because my grandmother assured me that she had already called the police, they were on their way and everything was fine.
"I wish I had contacted the police myself."
Both he and his wife have been charged with felony murder and conspiracy charges that could carry the death penalty if they are convicted.