He secretly filmed his stepdaughters while they were nude and tweeted explicit pictures of them, sometimes urging other users to share.
Now, the former Winnipeg youth-crisis worker will stay behind bars for four years after being sentenced Friday for making and distributing child pornography and voyeurism.
"What he did was disgusting," provincial court Judge Marvin Garfinkel said, his voice rising with apparent anger as he decided the case.
"This was planned and deliberate criminal activity that went on for a period of months," Garfinkel added. "It's terrible and it's horrible... the damage is incalculable."
The 47-year-old sex offender can't be identified under a court-ordered ban protecting the identities of his ex-stepdaughters and former common-law wife.
He began placing a hidden cellphone camera in the bathroom of their West End home in November 2012, filming the victims, aged 17 and 20, before and after they showered.
He transferred the videos to a computer, created still photographs from the footage and posted the graphic images to a public Twitter account, Crown attorney Adam Bergen said.
"Out of the shower, ready to party," read one caption. "The girlfriend," stated another.
Police ultimately recovered 24 images from the Twitter account deemed relevant to the case, Bergen said.
Many presented the victims fully nude and with their faces shown.
The offender was found out in an unusual fashion on Jan. 19, 2013.
One of the victims happened to be using Twitter and came across her own pornographic image.
After digging a little further, she also found images of her younger sister.
"She's obviously horrified," said Bergen. The pictures were posted by a user whose profile picture was of their stepdad, using his biological son's name.
Both victims went to their mother. The three confronted him and "in forceful terms" got him to turn himself in immediately.
"I recorded my girlfriend's daughters. I have ruined their lives," he told the overnight officer on duty at the Public Safety Building. He's been in custody since.
Police obtained a search warrant and seized computers, cameras and other devices from the home.
After finding the videos, they came across one that shows the offender setting up the camera in the bathroom before one of the victims comes into take a shower.
It then shows him removing the device very soon after she exits the room, court heard.
The man's crimes were an "unfathomable breach of trust," Bergen said.
It's unknown how many people on the Internet viewed, kept or distributed the photos, he said.
It's also possible they were shared across the Internet and not just on Twitter, court heard.
The man, described as "a loner" who has three kids of his own, offered officials no explanation for his conduct.
He's always said he didn't film the victims for sexual gratification and was perhaps "showcasing" the images to an imaginary group of online followers, defence lawyer Jeremy Kostiuk said.
After he's released, the man will be on probation for three years and must register as a sex offender for the rest of his life.