More than 70,000 registered sex offenders live in California, including about 7,000 sex offenders who are required to wear monitoring devices.
But at a time when more sex offenders across the state are becoming fugitives, keeping up with all of them can be a daunting task.
NBC4 rode along with parole agents in charge of keeping track of registered sex offenders in the San Fernando Valley.
Each agent is tasked with checking on between 20 and 30 sex offenders daily, making sure they stay away from parks and schools.
"If he's loitering, going around the block, or within 300 meters, that's going to raise a little flag," said parole agent Maurico Lopez, who uses a computer to track offenders.
While riding with parole agents, NBC4 came across one sex offender who has been on parole since 2008 for a conviction on child molestation and rape charges.
"I'm being monitored for no reason, just wasting tax money," said the man, who did not want to be identified.
The man said he had learned his lesson and would not offend again.
Parole agents say that's a story they hear from offenders all the time.
Some sex offenders don't wait for a parole hearing to decide their freedom, either, tampering with their GPS devices to get away. But agents say those offenders can't escape for long.
"We immediately submit warrants for their arrest," said Joe Martinez, with the Department of Corrections and Rehabilitation.