A Thornton Academy teacher has been placed on leave after the school learned of his arrest on charges of domestic violence assault, violating a protection order and possession of marijuana and paraphernalia.

Keith O’Leary, 50, of Saco was initially arrested Feb. 10 by police in Old Orchard Beach for allegedly violating a protection order granted to a woman who said she was his girlfriend.

O’Leary, a history teacher who also coaches volleyball at the Saco school, has denied he ever had a relationship with the woman and said he is being falsely accused by a disgruntled former employee of the Old Orchard Beach tavern he owns. The school placed him on paid leave when it learned of the charges, said Thornton Headmaster Rene Menard.

“This is an unfounded accusation and it will be proven that way,” O’Leary said in a telephone interview.

The domestic violence allegations first surfaced Dec. 21, 2015, when an Old Orchard Beach woman filed a temporary protection order against O’Leary. The woman did not respond to a request for comment Tuesday and is not being named.

In the protection order, the woman alleged that she and O’Leary began a romantic relationship in 2013 when she worked for O’Leary at another bar that he owned at that time.

O’Leary, who said he is separated from his wife and has two children under the age of 12, has denied ever being in a relationship with his accuser.

However, the woman alleged that O’Leary lived with her for a period starting in 2014, and that she helped him open Uptown O’Leary’s Tap in 2015.

Between July 2014 and December 2015, Old Orchard Beach police responded to O’Leary’s bar or to disturbances involving the woman and O’Leary seven times. Many of their quarrels were over a dog they adopted together, according to a police affidavit in support of his arrest.

The woman alleges that O’Leary forbade her from talking to his children, who were dropped off at the bar daily. He told the children that the woman was the dog walker, the woman alleged, according to court records.

In August 2015, the woman said that O’Leary had her arrested for criminal trespass at the bar “to teach her a lesson” because the dog was not at the bar when O’Leary’s children arrived there, according to the affidavit.

The dispute over the dog escalated, and O’Leary sent the dog to live with his wife for a time.

At various points in his interactions with police, O’Leary referred to the woman as an employee or ex-employee, indicating that he had fired and rehired her more than once. O’Leary called police multiple times because of the woman, according to the affidavit, alleging that she refused to leave.

In another incident, O’Leary said the woman tried to gain access to the bar to steal the dog, but police could not locate her.

The domestic violence charge was filed in relation to a confrontation on Nov. 6, 2015. The woman said that O’Leary threw her down a set of stairs, and spat in her face. The woman submitted to police photographs taken shortly after the alleged attack that show bruising and a black eye she suffered. The woman also submitted to police an audio she recorded of them arguing, in which O’Leary threatens the woman, matching previous descriptions of their confrontations, according to the affidavit.

O’Leary denied the charges, saying that he never had a romantic relationship with the woman, described her as a disgruntled ex-employee, and questioned her character and psychological state.

He also rebutted the marijuana and paraphernalia charges, saying the drugs and drug-related items belonged to a roommate.

“I’m stuck in a very sticky situation,” O’Leary said. ” I’ve been a straight shooter all my life.”