Adrian Bayley's former housemate tells the "story that could have saved Jill Meagher."

This man unknowingly lived with a monster.

Trigger warning: This post deals with rape and violence against women, and may be distressing for some readers.

A former housemate of murderer Adrian Bayley has revealed he once swung an axe at the serial rapist to save a woman during a sex attack at the home they shared.

The man – identified only as Barry – told Ten News he stopped an attack on a terrified and screaming woman in early 2012, about eight months before Bayley raped and murdered Melbourne woman Jill Meagher.

Adrian Bayley’s former housemate, “Barry”. Screenshot via Ten News.

Barry said he “ran in there with an axe, swung it at him.”

“My intention was never to hurt him, just wanted to scare him,” he said.

Related: Tom Meagher responds to the priest who blamed Jill Meagher for her own murder.

Barry said after stopping the attack, he drove the woman to Fawkner police station but she did not want to report the crime, saying she was “too afraid”.

Bayley is serving a life sentence for the vicious rape and murder of Ms Meagher in a Brunswick laneway in September 2012.

Adrian Ernest Bayley is serving a life sentence. Image via Twitter.

He has been convicted of sexually assaulting 12 women and was on parole at the time of the fatal attack on Ms Meagher, prompting questions about why he hadn’t been stopped sooner.

Barry said he had no idea he was living with a sex offender and trusted him enough to leave his five-year-old son in Bayley’s care.

He said the Adult Parole Board had not warned him that Bayley was on parole for five rapes and no parole officer had ever visited the house.

Murder victim Jill Meagher.

Barry said Bayley was “always out on the town” and boasted about having threesomes and picking up women in St Kilda, which he later discovered were rapes.

He said, otherwise, Bayley came across as a professional, tidy person who paid his rent – an “average Joe Blow”.

Bayley was jailed in 2013 for a minimum term of 35 years.

Last month, he was found guilty of raping three more women, two of them in the months before his fatal attack on Ms Meagher.

Bayley will face a pre-sentencing hearing at the County Court of Victoria next month.