The state Department of Corrections is investigating allegations that some guards at the Maine State Prison have harassed or intimidated other prison employees, according to two state lawmakers and a union official.

The probe at the facility in Warren, which houses more than 900 prisoners, may involve as many as 17 veteran guards, including one or more supervisors, who are allegedly targeting newly hired guards, according to an additional source with knowledge of the investigation.

The Department of Corrections has refused to reveal the scope of the inquiry, including how many employees are under investigation or the nature of the alleged harassment or intimidation.

The investigation comes on the heels of several recent security lapses at the state’s largest prison, including the murders of two inmates by other inmates in the past 13 months, as well as a change in department leadership. Former Commissioner Joseph Ponte left in April to head New York City’s jails and Associate Commissioner Joseph Fitzpatrick was appointed to replace him.

Both the internal affairs division and human resources departments of the Department of Corrections are investigating a complaint filed in July alleging that a group of employees has created a hostile work environment at the 916-bed prison for medium- and high-security inmates. Officials would not say how many employees had complained. The facility has more than 400 workers.

State Rep. Mark Dion, D-Portland, who serves as co-chairman of the Legislature’s Criminal Justice and Public Safety Committee, said he contacted the department’s legislative liaison, Associate Commissioner Jody Breton, this week to be briefed on what is happening, after learning of the investigation from the Portland Press Herald.

“There is an allegation of a hostile work environment,” Dion said. “The elements of a hostile work environment claim would involve conduct that is discriminatory against a person in a protected environment.”

Dion said personnel confidentiality laws limit how much he can say about the investigation. He said Breton told him the exact number of people at the prison who are under investigation, but he declined to share that number before any findings are made public.

“It’s a fine line between rude and boorish behavior, and behavior that’s trying to push someone out,” Dion said.

Dion, who served as the Cumberland County sheriff and ran the county jail in Portland before becoming a legislator, said he has urged the Department of Corrections to be more open about the investigation, but has met with resistance.

“I will say this: Rumors will rule the day, both for the public and for the employees (until the investigation is complete). I told the associate commissioner that I felt these types of complaints require an expedited inquiry,” Dion said.

Neither Fitzpatrick nor any of the department’s three associate commissioners responded to a request for comment on the investigation. Maine State Prison Warden Rodney Bouffard did not respond to a phone message.

Department of Corrections spokesman Scott Fish also did not respond to phone messages seeking comment, but did reply by email.

“If there is an ongoing investigation, the response would be the same as with all ongoing investigations: No comment,” Fish wrote on July 24.

Sen. Stan Gerzofsky, D-Brunswick, who serves as the other co-chairman of the Criminal Justice and Public Safety Committee, also confirmed he had direct knowledge of the investigation, having been informed last week by the Department of Corrections that it had been launched.

“I’m aware that there is something going on as chairman of the Criminal Justice and Safety Committee. I can’t comment on an ongoing investigation at all. This is in the early stage,” Gerzofsky said. “As soon as they come to a resolution, whatever that resolution is, I’ll have committee hearings on it.”

Jim Mackie, an official with the American Federation of State, County and Municipal Employees union, which represents state prison guards, confirmed that the investigation involves corrections officers whom the union represents.

“All I can tell you is that there is an investigation going on. I can’t tell you any more about it or what it involves,” he said.

Mackie said the federation represents rank-and-file guards, but not prison supervisors and other support staff.

“None of my guys have quit or resigned,” Mackie said.

Chris Quint, executive director of the Maine State Employees Association that represents other prison employees, including supervisors, said he was unaware of any investigation at the prison involving members of his union.

Ponte, the former commissioner, said shortly before leaving for New York City that the Department of Corrections has at times struggled to adequately staff the Maine State Prison because of high turnover and absenteeism.

Ponte spoke at a news conference in March after one inmate at the Maine State Prison was accused of murdering another inmate on Feb. 28 by stabbing him 87 times without guards noticing, and as Long Creek Youth Development Center in South Portland was seeing a spike in juvenile inmate violence. Ponte did not respond Thursday to a request for comment.

In the February inmate murder, 35-year-old Richard Stahursky is accused of assaulting a fellow prisoner, 37-year-old Micah Boland, in Boland’s cell, knocking him out, tying him up and stabbing him repeatedly with a pair of makeshift knives.

Boland’s killing was the second alleged murder of one inmate by another at the Maine State Prison since last summer. Alan Powell Jr., who was serving a 22-year sentence for murder, was allegedly beaten to death by Guy Hunnewell, another convicted murderer, in the prison’s exercise yard on June 25, 2013.