The state Department of Corrections is investigating the conduct of guards at the Maine State Prison for harassing or intimidating 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 be focused on as many as 17 veteran guards, including one or more supervisors, who are targeting newly hired guards, according to an additional source with knowledge of the investigation.

The Department of Corrections has refused to speak about the scope of the inquiry, including exactly how many employees are under investigation or the nature of the alleged harassment or intimidation. The timing of 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 and a change in department leadership with the departure of former Commissioner Joseph Ponte in April to head New York City’s jails and the appointment of Associate Commissioner Joseph Fitzpatrick as his replacement.

Both the internal affairs division of the Department of Corrections and its human resources department are conducting simultaneous inquiries into a complaint filed in July alleging that a group of employees have created a hostile work environment at the 916-bed prison for medium- and high-security inmates. The facility has more than 400 employees.

Rep. Mark Dion, D-Portland, 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 say what it is before any conclusive 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 was 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 transparent with the public but was 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 return a phone message.

Department of Corrections spokesman Scott Fish also did not return 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, the other co-chairman of the Criminal Justice and Public Safety Committee, also confirmed he had direct knowledge of the ongoing investigation. He said last week that he had been contacted by the Department of Corrections to inform him 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 involved some of the correctional 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,” Mackie said.

Mackie said that while AFSCME represents rank-and-file guards, it does not represent many prison supervisors and other support staff members.

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

Chris Quint, the executive director of the Maine State Employees Association that represents other prison employees, said he was unaware of any ongoing 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 struggled at times to staff the Maine State Prison adequately because of high turnover and guard absenteeism.

Ponte spoke at a rare 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 on Thursday to a request for comment for this story, through a spokesman for the New York City Department of Correction.

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 allegedly committed by another inmate 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.