DiGuglielmo's attorney didn't immediately respond to a phone message left Friday requesting comment.
In 1996, he killed 37-year-old sanitation worker Charles Campbell. Campbell had violated parking lot rules at the DiGuglielmo family's deli in Dobbs Ferry.
The policeman's father got into a fight with Campbell.
DiGuglielmo said he shot Campbell to protect his father, but he was convicted.
In 2008, a judge freed him after finding that a witness was pressured into giving testimony favorable to the prosecution.
The Appellate Division overturned that finding Tuesday.