Elliot Rodger’s dad to Barbara Walters: ‘My son was a mass murderer’

Peter Rodger, the father of Isla Vista gunman Elliot Rodger, told Barbara Walters in his first interview since the rampage that he didn't think his son could "hurt a flea" and that he has been living a "reverse nightmare" for the last month.

"Every night I go to sleep, I wake up and I think of those young men and young women that have died, and who were injured and were terrorized. And my son did that," Rodger said a clip released Thursday. "My son caused so much pain and suffering for so many families."

The interview will air at 10 p.m. Pacific on Friday during a special edition of "20/20." ABC News said Rodger sought out Walters for his first interview.

When asked by Walters about his life since his son killed six people and wounded more than a dozen others, Rodger said: "It's like a reverse nightmare situation."

"When you go to sleep normally you have a nightmare and you wake up and oh, everything is OK. No I go to sleep, I might have a nice dream, and then I wake up and slowly the truth of what happened dawns on me. And that is that my son was a mass murderer."

He continued: "There is no way I thought that this boy could hurt a flea .... we didn't see this coming at all."