The audit was requested by Fresno Assemblyman Henry T. Perea following the death of 10-year-old Seth Ireland who was beaten to death by his mother's boyfriend in 2008.
The investigation revealed that the addresses of more than 1,000 registered sex offenders matched the addresses of licensed foster-care facilities and homes, auditors found.
Specifically, the report said that 677 foster and group homes and other state-licensed facilities for children matched sex offenders' addresses, as well as 385 state-licensed facilities for vulnerable adults.
The auditor found that almost 600 of the 1,000 address matches were "high risk and in need of immediate investigation," the report said. It was not clear from the report how many foster and group homes are in California, in total.
This month, the state social services agency and county child welfare agencies investigated 99% of the matches and began legal actions against eight licensees of facilities, including four license revocations, said the report, titled "Child Welfare Services -- California Can and Must Provide Better Protection and Support for Abused and Neglected Children."
In six of those actions, registered sex offenders were living or present in the child facilities, and counties found 36 sex offenders having "some association" with foster homes -- prompting authorities to remove children from the facilities and ordering the offenders out of the homes, the report said.
The state Department of Social Services says it has begun licensing action against eight facilities and issued orders barring 36 individuals from facilities, according to the audit.
Individual counties are also taking action to remove children from homes or bar offenders from them.
The audit focused on Child Protective Services agencies in Sacramento, Fresno and Alameda counties.
Los Angeles County was also selected for review, but officials there refused to provide information requested by the auditor.

