DEER PARK - Opening statements were heard yesterday in the trial of a Deer Park mob boss accused of having an NYPD officer killed.

Prosecutors say Joel "Joe Waverly" Cacace had an NYPD officer killed because the cop married Cacace's ex-wife.

Officer Ralph Dols was gunned down at his Brooklyn home in August 1997.

Cacace is already serving a 20-year sentence after pleading guilty to ordering the murder of a federal prosecutor in 1987.