LOS ANGELES (AP) -- The father of the young man who killed six people and injured 13 others near the University of California, Santa Barbara, last month says it's his "duty" to help prevent future mass killings.
In a letter provided to ABC on Friday, Peter Rodger says he wants to help people recognize warning signs of mental illness within families.
He says his son, Elliot, hid his sickness from his family, mental health professionals and law enforcement. The father says in hindsight he is beginning to understand there are traits that family members can look out for in loved ones.
Peter Rodger also spoke to Barbara Walters in an interview to air Friday as an ABC News prime-time special.
Elliot Rodger died of an apparently self-inflicted gunshot wound after the May 23 rampage.