DOVER, Del. — The American Civil Liberties Union has settled a federal lawsuit stemming from an incident during which a Delaware state trooper ejected protesters from a book signing event with former U.S. Sen. Rick Santorum.

Under the settlement, the Delaware State Police will adopt a policy and training program for its officers on the free speech rights of protesters and pay $15,000 for the plaintiffs' legal fees, the ACLU said Wednesday.

In addition, state police Sgt. Mark DiJiacomo will write a letter to the plaintiffs. Former Santorum aides Ellen Melrose and Becky Barrett-Toomey also will send the plaintiffs a letter of regret and pay them $2,500, the amount they were paid by Santorum's campaign to assist him on a book tour in Pennsylvania and Delaware.

The plaintiffs intend to donate their damage awards to charity, the ACLU said.

According to the lawsuit, Melrose and Barrett-Toomey told DiJiacomo to remove four young women in advance of Santorum's arrival at a Barnes & Noble store on Concord Pike in August 2005 because they did not agree with the Pennsylvania Republican's views outlined in his book "It Takes a Family."

The plaintiffs alleged that their treatment violated their rights to free speech and assembly.

Barnes & Noble denied any involvement in the decision to have the young women thrown out, according to the ACLU.

Delaware State Police deputy superintendent Lt. Col. Mark Seifert denied that DiJiacomo violated the plaintiffs' rights. He attributed the incident to an "overreaction" by the store owner and Santorum's representatives.