Professor Joan Petersilia, an expert in parole reform, discusses the conditions of Phillip Garrido's parole on ABC's Nightline:

This man had the most stringent parole surveillance we give any sex offender in California. He was on GPS. We only have 7,000 – remember 7,000 of 300,000 registered sex offenders on GPS. So he had the most intensive surveillance the state has to give anybody. And still, for some reason, this situation was not uncovered. (5:05)

Well I think it's horrific. You couldn't help but being horrified that this was going on and in fact the authorities – both police, parole, and other law enforcement – wasn't on top of it. The man had been on parole supervision for over ten years, had not formally had any arrests or anything, so that from parole he had kind of fallen off the radar. (3:38)