Winnipeg police have arrested a suspected sex predator on suspicion he victimized a roommate's young daughters for years and groomed them as models for a child pornography collection.

'It looks like he was grooming these two little ones for a while.'—Const. Jason Michalyshen

The 23-year-old man will appear in a Winnipeg courtroom Monday morning to face a dozen charges including sexual assault, sexual interference, sexual exploitation and making child pornography.

Sex-crimes investigators arrested the man last week at the Winnipeg Remand Centre.

He was already behind bars awaiting trial on other charges dating back to May 2010, when the 39-year-old mother of two girls — aged 12 and nine at the time — called police and complained she had found child pornography on her home computer.

Police arrested the woman's roommate and charged him with possession of child pornography and sexually assaulting and interfering with the 12-year-old girl.

After his first arrest, officers in the Integrated Child Exploitation unit began a prolonged probe into the man's involvement with the girls.

'Extremely troubling'

Investigators uncovered evidence the girls were assaulted and interfered with over a period of years, court documents obtained by CBC News state.

They were also photographed in sexual poses and their images kept in a child pornography collection, according to police.

"It looks like he was grooming these two little ones for a while," Const. Jason Michalyshen said, adding the allegations against the man were "extremely troubling."

Other images police seized depicted boys and girls between the ages of eight and 16 involved in sex acts, police said.

Police said the suspect and the girls' mother had lived together since at least 2007 — first in a small community north of Winnipeg and later in a downtown home.

However, their relationship was "non-sexual," Michalyshen said.

Confronted relative with gun

The suspect has yet to make a bail application on the new charges. The allegations against him have not been proven.

According to court transcripts, his 2010 arrest came just after he finished serving a period of supervised probation in connection with a near-tragic incident involving a family member. 

In February 2007, the man burst into an older relative's rural Manitoba home while drunk and threatened him with a loaded revolver, according to court transcripts.

The relative was able to overpower him and knock the gun loose from the man's clutches. He fled the scene and was later arrested by RCMP.

The man pleaded guilty to possession of a dangerous weapon in November 2008 and was handed a six-month jail sentence to be followed by a year of probation.

He was also banned from possessing weapons for a 10-year-period.