SACRAMENTO  (AP) — The leader of the state Senate is seeking an independent review of how parole officers tracked a sex offender charged with four Southern California slayings, a spokesman said Wednesday.

Senate President Pro Tem Darrell Steinberg, D-Sacramento, will ask the inspector general of the Department of Corrections and Rehabilitation to review the monitoring of Franc Cano, 27, who was wearing a GPS-linked ankle bracelet when he and a co-defendant are charged with raping and killing four women in Orange County.

The inspector general previously found significant failures after investigating high-profile cases involving paroled sex offenders. Phillip Garrido was convicted of keeping Jaycee Dugard hidden at his Contra Costa County home for 18 years, while John Gardner III is serving a life sentence for killing two San Diego teenagers.

But Steinberg spokesman Rhys Williams said the Senate leader doubts the effectiveness of GPS monitoring as a deterrent, and may ask Inspector General Robert Barton to include that broader question in his review.

“Sen. Steinberg has a long-held concern about the effectiveness of GPS in preventing crime,” Williams said. “It’s pitched as an effective preventative tool, and the senator is concerned that isn’t the case.”

The Legislature is on spring break this week, and Williams said it is unclear how the request for a review will be phrased or how quickly it can be sent to the inspector general’s office. Steinberg will have to work through the Senate Rules Committee, of which he is chairman.

A corrections department spokesman, Luis Patino, could not immediately say whether the department planned its own review.

Cano’s co-defendant, Steven Dean Gordon, 45, was being tracked with GPS by federal parole agents at the same time.

Karen Redmond, a spokeswoman for the Administrative Office of the U.S. Courts in Washington, D.C., said she did not know if there would be a federal investigation into how Gordon was monitored by federal probation agents.