I've worked in journalism for nearly 40 years and no story, no documentary, moved me more than this one.

We wanted to achieve several things: To provide a comprehensive step by step account of how it went down, the events leading up to it, the shooting and the aftermath. It is a compelling story of "what ifs?" How innocent victims got caught in the wrong place at the wrong time, and how at least one person's life was saved by a last minute twist of fate. The lone survivor, Shayna Conway, speaks in detail about the tragedy for the first time.

We thought it important to convey the savageness of the attack. How the shooter stalked his prey, the number of shots fired, the number of times he reloaded, the damage done. Three promising young people cut down just as they started pursuing their dreams, and a fourth injured physically and emotionally forever. It is a life sentence of pain for Shayna and the victims’ families.

Why would Derek Jensen, described as a good son and friend, commit such a selfish, horrific crime? He was raised in a conservative home who turned away from his religion to become what they call in local slang a "Jack Mormon," Jack for Jack Daniels.

Isolated from his family and community, he became obsessively jealous and controlling, abusive and threatening. A breakthrough in our investigation came when we found his texts to Tabitha on her phone. We could trace the building rage and threats.

We hope this documentary adequately portrays the special character of the victims and their families. And we hope it can help women caught in controlling relationships, to understand they deserve respect, and if it doesn’t feel right, to reach out and talk to someone.

Larry Day produced, directed and co-wrote Road To Murder. He is president of Pyramid Productions, which produced the documentary in association with W5.