California parole officials say they have ordered increased monitoring of all sex offenders after recent high-profile lapses, most notably in the case of a young woman who was held captive for 18 years by a convicted rapist. The case is even more alarming since agents did visit the home where the girl was captive and reported nothing amiss.

The new policy requires parole agents to more closely track the movements of offenders using GPS-linked ankle bracelets. It also requires agents to visit high-risk sex offenders at their homes twice a month, up from one monthly visit.

Corrections officials are also reviewing whether they should have revoked the parole of John Albert Gardner III, a convicted sex offender now charged with murdering one San Diego County teen and being investigated in the death of another.

The policy changes are a response to a report in November from the department's inspector general that criticized it for missing chances to catch Phillip Garrido, who is now charged with kidnapping and sexual assault.

The new policy requires increased use of GPS tracking of those considered less likely to reoffend. Forty lower-risk offenders are supervised by each parole agent, compared with 20 high-risk offenders per agent.

Predictably Melinda Silva, president of the Parole Agents Association of California, said the increased workload will overwhelm agents charged with tracking the movements of 40 sex offenders. "We need to get them to 20-to-one," she said. "If they want to improve supervision, they've got to reduce caseload."