The Archbishop of Canterbury, Justin Welby, 68, was the spiritual leader of the global Anglican church. Over the past week, he resigned from his position after several reports came to light that he had ordered his institution to cover up the prolific abuse of boys and young men at the hands of religious leaders.

An investigation found that he failed to tell police about serial physical and sexual abuse by a volunteer at Christian summer camps as soon as he became aware of it.

Welby had been in office since 2013, and in his resignation, he apologized after the report described a barrister, John Smyth, who ran summer camps for young Christians, as the most prolific serial abuser associated with the Church of England.

Welby claimed he had “no idea or suspicion” of the allegations before 2013, but the independent report concluded that it was more likely than not he would have had knowledge of the concerns regarding Smyth in the 1980s. Welby also said he did not inform law enforcement agencies about the abuse because he was wrongly told that police were already investigating.

Church officials were first made aware of Smyth’s abuse in 1982, when they received the results of an internal investigation into complaints about his behavior at Christian summer camps in England. The recipients of that report “participated in an active cover-up” to prevent its findings from coming to light according to the report.

Smyth, who died in 2018, was held responsible for the violent, physical and sexual abuse of at least 115 children and young men in England, Zimbabwe and South Africa. Smyth’s actions weren’t made public until a 2017 investigation by Britain’s Channel 4 television station, which led police in Hampshire to start an investigation. Police were planning to question Smyth at the time of his death and had been preparing to extradite him.

Welby additionally apologized for “failures and omissions” in not properly investigating the claims.