CHICAGO — The pastor of a Chicago Catholic parish who was asked to step aside following allegations he sexually assaulted a minor 36 years ago was reinstated Friday.

In a letter to members of Christ the King parish, Cardinal Blase Cupich said Father Larry Sullivan has returned to duties because the allegations could not be substantiated.

Sullivan was asked to step aside last month after an accusation that he and another person attacked a woman in an alley in 1984 before he was to leave for the seminary. Sullivan was 18 years old at the time of the alleged attack.

Cupich said a thorough review was made by Archdiocesan Office of Child Abuse Investigations and Review and an outside investigator. He said multiple attempts to obtain information from the accuser was unsuccessful, which led to the allegation being unsubstantiated.

Sullivan, in a letter to parishioners last month, said that in 1984 while working at a fast-food restaurant he made comments to a female employee that upset her, resulting in her parents and police being contacted. He said there was no physical contact between him and the woman.

Sullivan has been pastor at Christ the King on Chicago Southwest Side since 2014, according to the archdiocese.