As the body count rises, it’s up to stage-struck Lt. Frank Cioffi (Ross Neuenfeldt) to herd the theatrical cats and figure out whodunit while simultaneously falling hard for the ingénue. In his third Hillbarn turn this season (after “The 39 Steps” and “Amadeus”), Neuenfeldt once again proved himself a deft comic everyman, with a sly, wry wit. This time he adds pleasing vocals and light-footed dancing to a not-so-bumbling Boston-accented Columbo.