From the cnn article you posted
Two Dozen Contacts
There were at least 16 visits from parole officers and seven by the fire department. There was also one by the sheriff's office responding to an allegation that people were living in the backyard. State and local authorities have now begun internal investigations to find out why none of these visits uncovered the existence of Dugard, now 29, and her children, Starlet, 15, and Angel, 11.
Then down the page:
Garrido, who had been released from prison after serving 11 years for a 1976 kidnapping, violated his parole in April 1993. It is unclear what he did or how the violation was flagged. As a result, he was placed in federal prison for one month and then released on house arrest for three months. He returned to the Antioch home, where he lived with his wife and his elderly mother.
And then this:
Betty Unpingco invited the entire neighborhood to her son's graduation party in spring 2006. She said Garrido attended and brought speakers for the party. When Unpingco and several adults noticed him talking to the high school girls, they asked him to leave. Later that night, she said, when they saw him waiting outside his home to speak to the girls, the adults escorted them home.
Feeling uneasy after the party, Unpingco checked the sex offender registry and found Garrido's picture.
"It was just so bizarre," said Unpingco, who has 10 children. "I warned my children to stay away from him and to always walk in twos." She did not notify police.
Hmm, yet another red flag ignored by police!
Thanks for the great link!