LOS ANGELES (AP) — An internal review by federal probation officials says officers properly supervised two sex offenders who are charged with the rape and murder of four women in Southern California.

The Los Angeles Times reported Thursday that the review praised probationagents for classifying Franc Cano and Steven Dean Gordon as high risk and warning them not to spend time together.

The reviewers say it would have been difficult to compare GPS data from the state system tracking Cano and the federal system tracking Gordon to see how often they disobeyed the warning.

Matthew Rowland, national chief of the federal courts' probation office, says there is no way to completely incapacitate offenders determined to commit new crimes.

The men were found together out of state in 2010 and 2012.