Officials in the United States have released a report detailing decades of sexual abuse by people associated with the Archdiocese of Baltimore, Maryland.

The office of Maryland Attorney General Anthony Brown released its 450-page report on Wednesday, identifying 158 priests accused of abusing more than 600 victims since the 1940s.

The release of the redacted report caps a four-year saga that began when an investigation was launched in 2019 by former Maryland Attorney General Brian Frosh. The probe was completed in November, after investigators reviewed more than 100,000 pages of documents, some nearly 80 years old.

Speaking to reporters on Wednesday, Brown condemned the actions of the local Catholic archdiocese.

“The incontrovertible history uncovered by this investigation is one of pervasive, pernicious and persistent abuse by priests and other archdiocese personnel,” he said. The report, he explained, described a cycle of “repeated dismissal or cover-up of that abuse by the Catholic Church hierarchy”.

Following the probe’s completion last year, Archbishop William Lori of Baltimore apologised “to the victim-survivors who were harmed by a minister of the Church and who were harmed by those who failed to protect them”.

Lori expressed “renewed shame, deep remorse and heartfelt sympathy” on behalf of the archdiocese.

Earlier this year, a judge ordered a redacted version of the report be made public.

The report painted a chilling picture of the Baltimore Archdiocese, the oldest Roman Catholic diocese in the country. It oversaw parishes, schools and congregations in much of the state.

In some instances, some church institutions housed more than one abuser at the same time.

Eleven abusers lived and worked at the St Mark Parish in the community of Catonsville, for instance, between 1964 and 2004.

“The staggering pervasiveness of the abuse itself underscores the culpability of the Church hierarchy,” the report said.

“The sheer number of abusers and victims, the depravity of the abusers’ conduct, and the frequency with which known abusers were given the opportunity to continue preying upon children are astonishing.”

The report adds to a growing list of sexual abuse allegations against the Roman Catholic church in the US and across the globe.

Revelations of widespread abuse — and systemic cover-ups — began with a 2002 report by the Boston Globe newspaper, which found its local archdiocese had attempted to conceal sexual misconduct for decades.

In recent years, the US Catholic Church has paid an estimated $3.2bn to settle clergy abuse cases, according to BishopAccountability.org, which tracks the issue.

Wednesday’s report does note that new national policies, following the Boston Globe’s exposé, have significantly improved the church’s internal handling of sexual abuse reports. But it still found numerous gaps in how the Baltimore Archdiocese combats abuse.

The report said that the archdiocese issued a public list of abusers that did not include all the cases it knew about. Some alleged abusers were also allowed to retire with financial support, rather than be removed, according to the report.

The investigation also revealed that the archdiocese failed to report many allegations of sexual abuse to authorities, conduct adequate investigations, remove abusers from the ministry or restrict their access to children.

In some cases, victims ended up reporting sexual violence to priests who were abusive themselves, prosecutors wrote.

The report’s release on Wednesday comes during Holy Week, considered one of the most sacred times of year in Christianity, as it comes ahead of Easter Sunday.

It indicated the number of victims is likely much higher. The report largely focuses on the years before 2002.