After allegations of harassment, intimidation, bullying — and possible criminal offences — perpetrated by guards at the Edmonton Institution, two correctional officers and two managers at the maximum security prison have been fired.

The unnamed employees were "disciplined and terminated," the Correctional Service of Canada (CSC) confirmed in a public statement on Tuesday.

An internal investigation is continuing, corrections officials said.

"Over the course of several weeks, allegations of inappropriate employee conduct were brought directly to the attention of the Commissioner of Corrections by staff and inmates at Edmonton Institution," the statement says.

"In response to these concerns, the Commissioner directed that an investigation be conducted to ascertain the exact nature and extent of these allegations."

Stan Stapleton, the national president of the Union of Safety and Justice Employees, says the firings show that CSC is taking the allegations seriously. The union represents employees at the prison who are not guards, such as parole officers, clerical staff, tradespeople and Aboriginal program officers.

The underlying culture, I would suggest, is still there. - Stan Stapleton, Union of Safety and Justice Employees

"The fact that there's strong action being taken is going to be a relief to certain employees that work there because now they will likely see that number one, the threat is gone. Threat of retaliation is gone," Stapleton said.

He says there's still a lot of work to be done to create a work environment free of intimidation and harassment at the prison.

"The underlying culture, I would suggest, is still there. Not as bad as it was," he said. "The concern they [the union's members] have is that if there aren't ongoing efforts to quash the intimidation and the bullying that this will take hold again."

Minister of Public Safety responds

The office of Ralph Goodale, the Minister of Public Safety and Emergency Preparedness, released a statement on Tuesday.

"Harassment is completely unacceptable," it states. "Public Safety Minister Ralph Goodale is committed to ensuring that the Correctional Service of Canada, and all of the agencies in his portfolio, are workplaces free from harassment and sexual violence.

"While we do not comment on personnel matters or matters under investigation by police, we applaud the Correctional Service of Canada for implementing a number of important initiatives to combat harassment in the workplace. These efforts are a positive step forward, and necessary to create a safe and healthy work environment.

"Corrections employees have a challenging job, and the vast majority work very hard and professionally to make a positive difference in the lives of the 23,000 offenders they are responsible for across the country."

The investigation began in 2017. Correctional Service of Canada commissioner Don Head flew to Edmonton's federal prison in mid-September to personally announce both criminal and administrative investigations.

The result of the disciplinary process shows that we are committed to holding employees accountable for their actions - Don Head, Correctional Service of Canada

Following a months-long inquiry, CBC News learned that at least seven employees — including some managers and acting managers — were walked off the property and suspended without pay around the same time as Head's announcement.

A third-party team tasked with looking into the situation confirmed a number of the allegations were true. Four employees have been fired as a result.

Additional disciplinary hearings are still pending, said CSC.

Edmonton police were informed of the allegations, and the force is still conducting its own separate investigation into any criminal misconduct.

CSC said it is fully co-operating with police.

The prison is under new management, and prison officials said they have brought measures to improve working conditions, including a new confidential tip line for employees to report misconduct, and increased training for staff to help prevent "inappropriate conduct."

New leadership at CSC

According to the statement, a new Regional Deputy Commissioner Prairie Region, France Gratton, and a new Edmonton Warden, Gary Sears, were appointed to the job.

"The result of the disciplinary process shows that we are committed to holding employees accountable for their actions," said Head in Tuesday's statement.

"We do not tolerate employee misconduct and all allegations are thoroughly investigated, regardless of the source."

Sources told CBC News the suspensions are linked to allegations of sexual assault, assault, harassment and employee misconduct.

Over the course of a year, CBC News interviewed seven past or present Edmonton Institution employees who say they have direct knowledge of sexual harassment, threats and intimidation by male staff against female employees at the facility. They say it's been happening for several years.

The sources said female staff in general — and female prison guards in particular — are targeted by some male co-workers with degrading comments, jokes, gestures and sexual advances.