Officials at McDonogh School in Owings Mills found evidence that five former faculty members allegedly sexually assaulted about two dozen students over several decades, according to a letter sent home with families Tuesday.

School administrators shared the details of an external investigation into the co-ed boarding school’s history of sexual assault allegations made against faculty members from the 1940s to the mid-1980s. None of the reports of sexual misconduct involved current faculty or students, the letter states.

A school spokeswoman did not return a request Wednesday for further comment.

The investigation was launched in 2016 after a former student, who attended the school in the 1980s, told administrators he was sexually assaulted by former faculty members Alvin J. Levy and Robert E. Creed.

Levy was indicted in 1992 by a Baltimore County Grand Jury on sexual abuse charges brought by a McDonogh graduate. He died before his scheduled court date.

Creed pleaded guilty in 1985 to a fourth-degree sexual offense and abuse of a minor, stemming from an incident with a McDonogh student in the 1980s. He has since died, school officials said in a previous notice from 2016.

After the school learned of the new allegations against both men in 2016, administrators notified police and hired New York-based firm T&M Protection Resources to conduct an external investigation.

This week’s letter details the firm’s findings, which were based on documents and interviews with 68 people, including current and former school faculty, alumni and former members of its Board of Trustees.

The firm found evidence corroborating the former student’s allegations against Creed and Levy, according to the latest letter. It also found that the same two teachers allegedly engaged in sexual misconduct with 19 male students over a period of four decades.

The investigation also found three other male former faculty members allegedly sexually assaulted five female students between the mid-1970s and the mid-1980s, according to the McDonogh letter.

McDonogh officials did not identify the three former faculty members and said in the letter that police have been notified.

A Baltimore County police spokesman was not available to comment Wednesday.

County State’s Attorney Scott Shellenberger confirmed Wednesday that the police department conducted an extensive investigation into the claims and contacted all alleged victims.

Of the former students who made allegations against the three unnamed teachers, one was willing to testify to the assault in court, Shellenberger said. However, the state’s attorney said he did not have enough evidence to build a case because the incident happened in the 1980s, when Maryland laws concerning sexual assault required the encounter to be forced or for the victim to be a younger age than she was.