About a year before we got involved with Darleen's case, her family worked with a private

investigator, Patrick Zerpoly, who goes by Zip to those who know him.

Zip spent his career with the Pennsylvania State Police.

He retired in 2015 as a corporal and the unit supervisor of the Criminal Investigation

Assessment Unit.

One of his specialties is Cold Case Homicide Investigations, and after retirement,

he's gone on to consult in cold cases.

Zip had the opportunity to review Darleen's case file, and he honed in on a particular

person of interest.

He cannot be ruled out as a suspect.

When you look at means, motive, and method and opportunity, he's the guy who stands up

above everyone else.

This is episode 12, P.I.'s Best Lead.

We're not using the real name of Zip's P.O.I. for legal reasons, so I'm going to call him

Daryl Lemon.

Daryl first came on the radar for police back in January 1985 via a tip from a woman

named Dolores, who worked at Young Door.

That's the same manufacturing company in Plymouth where Ron Holtz worked.

Dolores told police that during the summer of 1984, Daryl had been in Argus under,

quote-unquote, peculiar circumstances, and he had been staying at a home on 15 B.R.O.

just northeast of the Holes home.

This was on the edge of Argus, and he was staying with a couple named Larry and Bonnie

...