A former narcotics squad supervisor pleaded guilty Monday to a federal crime - lying to a FBI agent.

Mathue Phares, 38, served nearly 18 years with the Richmond County Sheriff's Office. He was a sergeant assigned to narcotics until he was forced to resign in December while under investigation.

The sheriff's internal affairs office asked the FBI to investigate allegations of civil rights violations, FBI Special Agent Jeffrey Downey testified Monday in U.S. District Court.

Some of the allegations included claims that Mr. Phares had sexual relations with confidential informants. That could be a civil rights violation because an officer is in a position of power or authority over an informant, Agent Downey said.

When agents called Mr. Phares in for an interview Dec. 11, he initially denied ever having an improper relationship with any informant during his career. He later admitted to one sexual relationship, Agent Downey testified. Federal agents then learned there were more than one, a fact that hampered their investigation, the agent testified.

Mr. Phares will remain free on his own recognizance until sentencing.

A hearing has not been set. The maximum penalty is five years in prison, though the harshest penalty is rarely imposed in federal court, especially when the defendant has no prior record.