Missy's clerical job at the police department didn't cause her hobby, but it certainly led the way.

Since she had to drop off paperwork at the morgue anyway, and the bodies weren't guarded (why would they be?), she began checking out the male corpses, and after a time she decided to take souvenirs from most attractive ones, and sliced off their Best Parts and strung them along the bottom of wire clothes hangers and hung them in her hallway closet to dry.

As fate would have it, one day there was a shooting behind the police station.  In the chaos following, she noticed the fresh corpse was particularly charming and retrieved its Best Part for her growing collection.

Freshness does matter, as Missy discovered.  This Best Part didn't shrink as much and hung better on the hanger than the ones from stale corpses.  So, of course, she had to go fresh from then on.

Bars were the best collecting grounds.  Missy, as always, was choosy.  She picked the handsomest men staggering drunk into the parking lots to the most exquisite cars.  They all readily acquiesced to the smiling young woman who offered to drive them home, but none reached home and their Best Parts took up residence in her closet.

"STOP THE SICK SERIAL SLICER!" screamed the press.  A foreign man who smuggled tiger scrotums was briefly detained, and later shot by the wife of a victim, but the police had to admit they had no strong suspects.

By this time, Missy's enthusiasm for her hobby had begun to wane.  When she purchased an aquarium and filled it with colorful tropical fish, her old hobby completely faded from her mind.

A clutter show Missy watched ultimately got her caught.  The show advised boxing up anything you haven't looked at for six months, waiting another six months, then if you can't remember what's in the boxes, give them straight to the charity shop.  Imagine the surprise of the charity shop volunteers when they unboxed hangers full of dried Best Parts.

When asked: why, Missy, why, she replied, "That was before I discovered fish."