An elite private school in Brooklyn is investigating reports that former employees engaged in past "inappropriate physical contact" with students, according to letters to alumni viewed by BuzzFeed News.

Vince Tompkins, the head of Saint Ann’s School, laid out the developing investigation in three letters sent to the wider school community between October 2017 and March 2018. Some of the allegations, he wrote, involved people who were students at the time of the reported incidents. None involve current students at the school.

"I am not able to answer any questions or share any information other than what is in the letters that Saint Ann’s has sent to our community about what is an ongoing investigation," Tompkins said in an email to BuzzFeed News. "We continue to gather facts and follow those facts wherever they may lead us, with the fullest possible regard for privacy of victims, witnesses, and those accused."

The outside investigators the school hired didn't immediately return requests for comment.

Tompkins and Jonathan Weld, the president of the board of trustees, wrote a letter to the Saint Ann's School community in October 2017 about "reports that have recently come to our attention regarding inappropriate physical contact with students by past employees of the school. These reports date to the 1990s and before, are to date small in number, and do not extend to any current administrators, faculty, staff or students."

"To distort the boundaries of the student-teacher relationship is antithetical to our school's most deeply-held values and undermines the foundations of our educational mission," the October letter reads. "Such behavior is not, and will not be, tolerated at Saint Ann's." The school didn’t elaborate on the allegations.

Then, on Thursday, Tompkins sent a letter to alumni saying that the external investigators the school hired are looking into alleged incidents of "inappropriate physical contact" that took place as far back as the 1960s. The school was founded in 1965.

"The investigators have conducted interviews with many individuals over the past several months, some of whom were witnesses while others were victims of alleged inappropriate physical contact," Thursday's letter said. "The earliest of these alleged incidents took place in the 1960s while the most recent took place in the early 2000s."

Saint Ann's, in Brooklyn Heights, charges from $38,000 to nearly $45,000 per year for tuition. The school counts Lena Dunham, Jennifer Connelly, and designer Zac Posen among its famous graduates.

The school said in the letter that the investigation is ongoing and they expect it to conclude in the next several months.

Separately, in a letter to faculty and staff dated January 2018, Tompkins said that "an experienced outside investigator" found that the former head of the middle school had allegedly "violated a number of school policies and engaged in behavior that was inconsistent with his responsibility to act in the best interests of Saint Ann's students and the school community," according to the January 19 letter. Specifically, the allegations included inviting students and recent graduates to his home and “serving them (or permitting them to bring and to use) marijuana and alcohol.”

Thompson wrote in March that "soon after we wrote to the community last October, the school became aware of concerning interactions between" the former head of the middle school and recent alumni. "We hired a separate external investigative firm to look into this matter," he said.

The school accepted his resignation.

Thompson said that head of middle school, who worked at Saint Ann’s since 2002, was reminded by his colleagues about the importance of maintaining appropriate boundaries with students and young alumni, according to the letter.

Investigators also claimed he gave false, incomplete, or "less than forthright" statements to Tompkins when confronted about his behavior in late 2017.

Investigators said they have no evidence "that any of these behaviors involved students currently enrolled at Saint Ann's."

The October letter: