CONCORD, N.H. (AP) — An independent investigation into sexual misconduct at a New Hampshire prep school has now substantiated abuse claims against 20 former faculty and staff members dating back decades including a former Massachusetts congressman.

St. Paul's School released two reports after an independent investigation in 2017 detailing allegations against 17 people who worked there between 1947 and 1999. An addendum released Tuesday includes the names of three additional people who allegedly committed abuse between 1967 and 1988.

The list includes former teachers, administrators, chaplains and a counselor accused of a range of misconduct from inappropriate touching to forced kissing to one teacher who allegedly took students on several trips to New York City to have sex with prostitutes.

Investigators also found evidence the school failed to protect students at the time or fully investigate their complaints. Several of the accused were fired, but most were quietly "moved on" with letters of recommendations for their next jobs, according to the Boston law firm Casner & Edwards.

St. Paul's requested the investigation last year following reports about Howard White, who taught at St. Paul's from 1967 to 1971 and pleaded guilty to sexually assaulting students from St. George's School in Rhode Island in 1973.

In the latest report, investigators said they were able to substantiate allegations against the late Massachusetts Congressman Gerry Studds, who was described as preying on male students during his time there from 1965 to 1969.

Studds, who was censured by the House in 1983 for having an affair a decade earlier with a 17-year-old congressional page, is described by one student in the report as "a predator." Another detailed how he passed out at Studd's apartment after smoking marijuana, only to find Studds rubbing his bare chest. The student immediately jumped off the bed and ran out of the apartment.

Another teacher detailed in the report, David Pook, was sentenced Friday to four months in jail for telling a former student to lie about their relationship to a grand jury investigating sexual misconduct. Pook, of Warner, had taught at St. Paul's for eight years. He was arrested in February.

"Our goal has been to uncover and shed light on a dark part of the School's history with the hope that transparency will promote healing in our community," Interim Rector Amy Richards and Board of Trustees President Archibald Cox said in a letter to the school community.

"These stories are devastating but as difficult as they are, we are thankful for the survivors who came forward to share them," they wrote. "While we cannot change the past, we commit ourselves to support those who experienced abuse while at the School, and to ensure a healthy community for today's students."

The latest revelations prompted at least one group to call on St. Paul's to do more to ensure the abuse doesn't happen again.

"We're saddened to learn that additional alumni were harmed by faculty and staff at St. Paul's School," said Amanda Grady Sexton, a spokeswoman for the New Hampshire Coalition Against Domestic and Sexual Violence. "We offer support and solidarity to the brave survivors that have come forward, and we hope that their efforts to shatter the silence around decades of abuse on campus will help the School appropriately address the glaring need for change."

The school is facing several lawsuits and an investigation by the New Hampshire Attorney General's office over the finding in its report.

Since the allegations were brought to light, the school has embarked on a series of reforms aimed at preventing abuse, support victims and encouraging the reporting of any wrong doing. Earlier this summer, it announced three initiatives to support abuse survivors: an independent arbitration system for those seeking monetary compensation, an alumni-led effort to encourage further discussion and the victims' therapy fund.