New Haven Police Department Chief Dean Esserman verbally harassed an usher working at the Yale-Army football game in September, claimed a letter to the Board of Alders from an assistant Yale professor.

The board received an email from Daniel Weinberger, an assistant professor of epidemiology at the Yale School of Public Health, suggesting that Esserman’s conduct was inappropriate, especially given his position. Weinberger wrote the letter after he witnessed the police chief repeatedly harass the usher.

“I would like two outcomes from this situation,” Weinberger wrote in the letter, a copy of which was published by the New Haven Independent. “First, I would like to ensure that the usher does not lose his job over this incident. Second, I think it is critical that the city examine the behavior of the chief to ensure that this is not part of a broader problem in police management and conduct.”

Following the publication of the email, Esserman has acknowledged that his actions were improper and apologized, the Independent reported.

Weinberger, who arrived at the game about an hour before kickoff, said Esserman and his guest, a young man, refused to show the usher their tickets when he stopped them as they were walking down the stadium steps. Esserman claimed he had an “‘all access pass’” as police chief, Weinberger said.

According to Weinberger, after Esserman walked away, the usher said privately to him and his wife that the police chief was a “‘jerk’ (or something to that effect),” at which point, Esserman turned back and “began to harshly and loudly yell” at the usher.

Esserman asked to speak with the man’s supervisor and threatened to “‘shut the whole game down’” if the supervisor did not have the usher removed from the premises, Weinberger added. He said he left his seat to intervene after hearing Esserman’s threats.

“I told the supervisor (while the chief was standing there) that the man had simply been trying to help us find our seats,” Weinberger wrote in his email. “At this point, the Chief turned to me and badgered and mocked me and asked if I wanted to make a statement.”

Weinberger added that Esserman followed him to his seat, and they continued to discuss the issue. He said the usher’s supervisor thanked him later for defending his employee.