Keith Morrison

People's lives have been changed forever.

As long as there's breath in my lungs, we aren't going to give up.

And David Corvo is Senior Executive Producer.

From NBC News Audio, Bryson Barnes as technical director.

Sound mixing by Bob Mallory.

Nina Bisbano as associate producer.

The Mojave Desert was beginning to bask and bloom in the late winter sun.

Just beyond the sand in the city of Palmdale, the grass was greening out of the cypress trees at Desert Lawn Memorial Park, where Michelle O'Keeffe had been laid to rest.

The inscription on her stone?

Cheerful, loving sister and daughter.

At her funeral, with his mother's hand on his shoulder, 12-year-old Jason made his sister a promise.

Michelle's father, Mike O'Keefe.

Impossible not to ask.

Impossible to answer.

But there was a second question, too.

A question that would not leave him alone, that tormented his every waking moment.

Who did this thing?

Mike O'Keefe would do anything to find out and get justice for his daughter.

Anything.

In this episode, you'll see how far a family will go to get answers.