PORTLAND — A western Maine man serving a life sentence for a double murder says he should have been able to suggest at trial that someone else carried out the killings.

The Sun Journal reports that John Jenness Jr., the lawyer for Duane Waterman, told Maine Supreme Judicial Court justices Wednesday that he should have been allowed to introduce an alternative suspect at Waterman’s trial last year.

But Assistant Attorney General Donald Macomber argued that trials aren’t meant to be fishing expeditions to divert suspicion from the defendant.

Waterman was convicted in the deaths of 50-year-old Timothy Mayberry of West Paris and 43-year-old Todd Smith of Paris. Prosecutors said the 2008 shootings at Mayberry’s home stemmed from a dispute over money and drugs.