Massapequa, its residents proudly proclaim, is a "cop town."

Perched on Long Island's idyllic South Shore, it is just an hour's journey via train from Manhattan.

The community is home to New York Police Department (NYPD) detectives, multi-generational cop families, officers from Nassau and Suffolk Counties and members of myriad other law enforcement agencies.

And when body parts started to be discovered in 2010 on Gilgo Beach - not far from where local teens lifeguard and families gather in summer - it became clear that a serial killer had been active on Long Island for years.

The rumour mill went into overdrive. Was he local? Was he still hunting? And was he, after operating for so long without getting caught, perhaps even wearing a badge?