Former Calgary teacher Christian Sarile has pleaded guilty to 17 charges involving dozens of child victims over an eight-year period.

The sexual predator admitted to targeting girls as young as 12 whom he would pay to perform sexual acts. At the time of his first arrest, in May 2017, Sarile was a Grade 6 teacher and also taught music.

The Calgary police investigation dubbed Operation Choir found Sarile would pay the underage girls in money, drugs, alcohol and vaporizers in exchange for sex and nude photos.

On Thursday, Court of Queen's Bench Justice Earl Wilson accepted the plea negotiated between prosecutors Martha O'Connor and Aurelie Beland and defence lawyer Yoav Niv.

He pleaded guilty to charges of sexual assault, paying minors for sexual services, sexual extortion, luring and making child pornography.

A 78-page agreed statement of facts was read aloud by the two prosecutors, giving the disturbing details of each of Sarile's crimes involving every victim.

Threats and bribes

In several cases, Sarile targeted girls who were particularly vulnerable — one teen was drunk, another told Sarile she was cutting herself. He even targeted children who attended the schools where he worked.

Sarile sent tens of thousands of messages to his victims over various social media sites like Snapchat, Instagram and AskFM.

When the girls stopped sending him sexual photos, Sarile threatened to send the nude images to their friends and families.

In the summer of 2016, Sarile met one of his victims, whom he began paying for oral sex. She was 14 at the time; he was 26 years old.

The girl had two friends who were 13 and 14 and both of those girls also began sexual relationships with Sarile, who was lying about his identity and age.

On one occasion, Sarile made the girls wear blindfolds while they took turns giving him oral sex in the back of his father's van. He made a video of the encounter, which was later recovered by police.

In several cases, while pretending to be someone else, Sarile would contact his victims and threaten them if they did not perform sexual acts. Out of fear that he would release their nude photos, some of the teens complied and had sexual contact with Sarile.

Taking advantage

After Sarile was arrested on May 2, 2017, he admitted he knew the girls he'd had contact with were underage and that he'd been taking advantage of them. He said he knew what he'd done was wrong.

Calgary police were concerned about the possibility of more victims so a press release was sent out on May 3, 2017. Investigators were contacted by 30 people.

He was released on bail but Sarile continued to prey on underage girls.

On Dec. 5, 2017, while under police surveillance, Sarile was observed picking up a 14-year-old at a Calgary junior high school. He drove to an LRT parking lot where she performed oral sex on Sarile before she got out of the car and he drove away.

Police accelerated their planned arrest of Sarile to Dec. 7, 2017. He has been in custody ever since.

A sentencing hearing will take place later this year.