DETROIT — A principal at Holy Redeemer Grade School in southwest Detroit has been placed on administrative leave after a civil lawsuit alleged he sexually assaulted a woman decades ago.

John Patrick Kiley was placed on leave Oct. 31 after a woman claimed Kiley assaulted her from May 1989 to June 1991 both at her home and at St. Bede Elementary in Southfield, which has since closed. The woman is suing Kiley and also names the Archdiocese of Detroit as a defendant.

Communications Director Ned McGrath said the matter was being treated seriously. “These are serious allegations, and we intend to fully investigate this matter,” he said.

The lawyer of the woman filing the lawsuit, Frederick Livingston, said no legal action was ever filed because the victim was unwilling to cooperate and had denied any improper action on the part of Kiley. He said she was now bringing the lawsuit as a result of emotional damage from the incident years later.

The lawsuit seeks damages of at least $25,000 and is being heard by Judge Colleen O’Brien.