Transcript for Santa Barbara Tragedy: Peter Rodger's Mission
S the the -- it is the mission of a heart broken father, peter roger. His son killed six people and then himself. Tonight he is speaking out and calling for change in how he handling the mentally ill. ABC has the story. Reporter: It's the crusade peter roger never wanted. I think mental illness is the big elephant in the room and this country needs to get up and look at it. Reporter: Roger is on a mission calling on families, police and the mental health community to work harder identifying people like his son before it's too late. You have to remember that Elliott was a very high functioning individual that had social issues. That's the way we regarded him and the therapist regarded him. Reporter: He says Elliott was never officially diagnosed but in hindsight there were signs. Breaking news right now. We are getting reports of a shooting. Gun fire. Reporter: Weeks before the murders Elliott posted this disturbing video on youtube. I hate all of you. Reporter: Police followed up but left convinced he was not a danger. Peter roger doesn't blame police but wants the system to change. He believes if the officers were required to have a trained social worker with them and the ending would have been different. Then it would have been evident that something was wrong and a social worker would have picked up that change of behavior. Reporter: Even with the changes there is no easy fix. Experts say families cops even professional therapists can still be fooled. One of the difficult parts of psychiatry and mental health is there's no blood test, no x-ray, no magic, you know, test to know whether somebody is lying or not. Reporter: Another challenge is that young adults like Elliott can't be forced to take medications that might help. Here's the problem. I'm going to bring this up right now. When somebody is over 18 and they refuse medication, it is impossible for you as a parent or a family member to make them take that medication unless they do it voluntarily or if they commit a crime. Nor can you hospitalize them or institutionalize them? No. They have to commit a crime before you do that. Reporter: Elliott's crime would claim six victims. His father is dedicated to helping other parents see what he didn't. By looking at the red flags and markers, the common traits between perpetrators, asking families to understand love and support children that might be in the same position as Elliott, they need to get help, they feel in any way that they might have another Elliott. Clayton Sandell ABC news, den search. Our thanks to Clayton Sandell. And if you have questions or want more information, go to our website abcnews.com.
This transcript has been automatically generated and may not be 100% accurate.