The Everett Herald reports the Snohomish County medical examiner's office was not able to determine if the punch, which knocked down Harold E. Caywood, was the cause of his death weeks after the violent robbery. The medical examiner said Caywood had other pre-existing medical conditions.
Prosecutors then decided not to pursue murder charges against Patrick Hartness.
The 26-year-old Hartness admitted on Friday he robbed Caywood in August. Prosecutors want a 10-year sentence.
Caywood's family says he was a World War II veteran, who before the attack was an active man, making elaborate beading projects that won prizes at the Evergreen State Fair.