LOS ANGELES (AP) –Lindsay Lohan is under investigation for an alleged misdemeanor battery against a female staffer at a rehab facility where the actress is receiving treatment, authorities said Tuesday.

Riverside County sheriff’s Deputy Herlinda Valenzuela said officers responded to a Betty Ford Center facility in Palm Desert on Dec. 12 shortly after 1 a.m. for an incident involving Lohan.

Valenzuela says a female staffer reported having a dispute with the “Mean Girls” star and that she wanted to pursue charges. No arrests were made and Valenzuela says detectives continue to look into the case.

Their results will be presented to Riverside County prosecutors, who will decide whether to file a criminal case, Valenzuela said.

Messages for Lohan’s attorney, Shawn Chapman Holley, were not immediately returned. An e-mail message seeking comment from a Betty Ford spokesman was not immediately returned, although the facility does not comment on its patients.

Lohan has been receiving treatment at the Betty Ford Center and its facilities, about 120 miles east of Los Angeles, since late September.

A judge overseeing her probation for a 3-year-old drunk driving case has required Lohan to remain at the rehab center until Jan. 3.

Los Angeles Superior Court Judge Elden S. Fox has scheduled a hearing on Lohan’s progress for Feb. 25. He has said he would be willing to place her on informal probation and allow her to leave Los Angeles if she stayed out of trouble until then.

Lohan’s stint at Betty Ford is her fifth stay in rehab and her second this year. Fox agreed to release her early from treatment at Ronald Reagan UCLA Medical Center in late August, but she failed a drug screening within weeks.

Fox opted to send her back to rehab rather than jail, where she would have been released early due to overcrowding.

The battery investigation was first reported by celebrity news website TMZ.

(Copyright 2010 by The Associated Press. All Rights Reserved.)