LONDON (AP) — The head of an abbey on a monastic Welsh island apologized Tuesday after a review found that a monk sexually abused children over several decades “in plain sight" despite repeated complaints raised against him.

The review said victim testimonies dating from the 1970s suggested that Father Thaddeus Kotik, who died in 1992, was a “serial and prolific” child abuser on Caldey Island, a tiny community home to Cistercian Order monks off the coast of south Wales. The scenic island and its abbey are popular tourist attractions.

Victims alleged that Kotik used sweets, chocolate and a tortoise to lure girls and boys to isolated locations on the island, and that he befriended families living on the island with affection, gifts and babysitting offers to access the children.

Father Jan Rossey, the abbot of Caldey Abbey, apologized for a “closed culture of secrecy and cover-up” that kept the abuse hidden for so long.

“It is clear opportunities were missed to stop the abuse of children. It is particularly heartbreaking to hear children spoke up to adults and no action was taken,” he said in a statement Tuesday.

Kotik died in 1992 without being charged or convicted of any of his alleged crimes.

Abuse allegations have been made public since 2017 after six women made a legal claim stating that Kotik had sexually abused them between 1971 and 1987. The claim was settled with a financial agreement but the abbey did not issue an apology.

The independent review was launched earlier this year, when a victims' campaign group said around 50 people had come forward with allegations they were abused by monks on the island.

The review examined allegations made by people who lived on or visited the island as children, and included accounts of victims being fondled or held too tightly. One victim said he was raped by Kotik.

“There appears to have been a failure of leadership at the highest level within the Order and Abbey. Serious matters of repeated and frequent allegations of child sexual abuse by (Kotik) were not reported to the statutory authorities as the law of that time required,” the review said.

Rossey, the new abbot, pledged to create a more open and transparent culture and to put in place safeguarding improvements on the island.

The Cistercians, who are a stricter offshoot of the Benedictine Order, have been living on Caldey Island for over 1,000 years. The island promotes itself as a haven of peace and is described on its website as “one of Britain's holy islands.”