A jury last month convicted Edward Ates of shooting and killing Paul Duncsak in Duncsak's northern New Jersey home in Ramsey.
During the six-week trial, Ates' defense rested on claims that he was too fat to have run up and down stairs to shoot Duncsak, then escape by driving more than 20 hours to his mother's home in Louisiana.
Ates was 62 years old and 285 pounds when Duncsak was killed in 2006.
Prosecutors are expected to ask for a sentence of life plus additional time. Ates' attorney plans to appeal and says the killer is still on the loose.