A SUPERVISOR in the Chester Police Department has sued the mayor, the police commissioner and the city for slander, defamation and libel because, he says, the mayor and commissioner have been spreading rumors that he's being investigated by the FBI.

According to the suit, filed Tuesday in the Delaware County Court Common Pleas on behalf of Lt. Col. Darren Alston, Alston learned of the rumors after being demoted from chief of police when new Mayor John Linder took office early this year.

Linder appointed Joseph Bail Jr., who had retired from the department as a major in 2010, as the new chief.

Following the change in command, Alston began hearing rumors around the department that he had been demoted because he was under investigation by the feds for being involved in illegal drug or gun sales, the suit says.

Sometime this summer, Alston ran into state Rep. Thaddeus Kirkland and, during a discussion of crime in Chester, Kirkland allegedly told Alston that Linder had told him he had demoted Alston because he was being investigated.

About two weeks later, during a meeting with Kirkland, the city solicitor, the chief of staff to City Council and two councilwomen, Alston allegedly was told by all present that Linder had informed them that the FBI was investigating Alston. Those at the meeting said that Bail had been Linder's source of information, according to the suit.

Alston, a 19-year veteran of the department, claims that he has never been under federal investigation. He's seeking an injunction to get Linder and Bail to refrain from making false statements, and he's suing both men and the city for damages.

He claims that the rumors have caused him emotional and physical distress, including "headaches, sleeplessness, nausea, and feeling of physical un-wellness."

Alston's attorney, Joseph Oxman, said that he has no idea why Bail and Linder allegedly spread the rumors but that he believed that Bail was behind them.

He said that his client's lawsuit has nothing to do with his demotion.

"When Mayor Linder demoted him, he understood that's part of the political process," Oxman said, "but he never expected to be demoted and defamed."

Alston is still active with the Chester police.

Calls seeking comment from Linder, Bail, Kirkland, the city solicitor and an FBI spokesman were not immediately returned.