Up next, a young girl witnesses her mother's murder.

And is this his bleeding?

I'm okay.

But for years, the crime goes unsolved.

This was somebody that Crystal knew,

and probably knew well.

A suspect comes forward with an unbelievable tale.

And it was as the most bizarre story I'd ever heard in my life.

It's completely impossible.

But what if the evidence shows he's telling the truth?

The DNA come back and DNA does a lie.

You can't believe it.

In the summer of 1992,

Crystal Perry bought a small house in Bridgden, Maine.

The single mother thought it would be the perfect place to raise her daughter Sarah.

My mother's number one priority was taking care of me,

and she did all she could to, you know, buy a house for us as soon as she could

and make sure that, you know, I had to really stable up bringing.

Crystal found work in a local shoe factory,

and by all accounts, was a good parent.

Whoever you meet to speak with her, they'd say she worked very hard at the local shoe shop

trying to make a better life for she and Sarah.

...