PITTSBURGH — A city police officer was convicted Tuesday of drunken driving and involuntary manslaughter in an off-duty motorcycle crash that killed his fiancée’s friend.

But Allegheny County Judge Jeffrey Manning found Adam Lewis, 31, not guilty of homicide by vehicle while driving drunk, which means the judge didn’t believe the officer’s intoxication led directly to the fatal crash in 2010.

Lewis’ conviction on the lesser manslaughter count means the judge found the officer was reckless and showed gross negligence in the crash that killed 28-year-old Jessica Marie Lojak, of Fawn Township.

Lewis was fired in March 2011 and likely faces incarceration when he returns for sentencing Jan. 6 before Manning.