Up next a desperate woman struggles to survive. She was trying to get to the phone.

Hard to say if that was before or after she was shot.

Police have a solid suspect, but he's got an airtight alibi.

This is not your prototypical killer. We were looking everywhere to try to get to the bottom of this mystery.

The killer knows how to destroy evidence and nearly succeeds.

I've had a number of cases where individuals have tried to obliterate the microscopic marks produced by the barrel.

Luckily for forensic scientists, some of these folks don't know what they're doing. Southern Pennsylvania is

with numerous small towns and communities centered around farming and agriculture.

York County, Pennsylvania, is right along the border with Maryland, with a history that goes back prior to the Civil War.

It has some involvement in the Battle of Gettysburg.

Violent crime is... in the Battle of Gettysburg.

Violent crime is a rarity in the area. So when on a March afternoon in 2010,

a 911 operator got a call with no response on the other end.

It was assumed to be an accidental call.

York County 911 dispatcher 65.

Hello?

99% of those.

99% of those

99% of those turn out to be totally nothing nothing either a kid playing with a phone or

or something along those lines. It's nothing that would raise an alarm.

The York County Control hung up the phone and called back and received a busy signal so that means the line is still open.

The call was from the landline, from the home of a 55-year-old woman named Monica Schmeyer.

...