Nine people across central Ontario including a longtime teacher face child pornography or sexual assault charges after police say they interrupted a network of online child predators that allegedly preyed upon two young sisters in Hamilton.

Hamilton Police Det. Sgt. David Dunbar says Children’s Aid officials came to them on May 3 after a seven-year-old girl told child welfare authorities she was being sexually abused by her mother’s boyfriend.

Police arrested a 34-year-old man later that day. Upon a search of his home, police located several computers, hard drives and memory cards that allegedly contained images and video of several other individuals sexually assaulting the young girl.

Dunbar alleges the suspects were sharing the images and video with each other online and even set up a Craigslist ad to locate another underage victim who could be preyed upon.

Police also arrested the girl’s mother, a 39-year-old Hamilton woman, and charged her with failing to provide the necessities of life.

Over the next four months, Dunbar said four other suspects —a 36-year-old Hamilton man, a 50-year-old Hamilton man, a 38-year-old Waterloo man and a 48-year-old Waterloo woman were arrested and charged with various child sex and pornography offences. Their identities cannot be made public because of a publication ban on the case.

Two other suspects, a 52-year-old St. Catharines man and a 35-year-old Waterloo man, were also arrested and charged with child pornography offences.

“These arrests have prevented other children from being abused or being exposed to other dangers,” Dunbar said.

Dunbar said the young victim’s older sister, who he said is no older than 16, was also allegedly preyed upon by this group and assaulted.

Dunbar said Hamilton Police shared the digital evidence they collected with several other Ontario police services and U.S. Homeland Security, leading Niagara Regional Police to share information regarding a 48-year-old Kitchener man named Geoffrey Burnet.

Burnet allegedly made, accessed and downloaded child pornography shared by others arrested in this investigation.

But after further investigation, Dunbar said Burnet is also now facing sexual assault and indecent act charges related to the unrelated historic sexual assault of another underage girl dating back to 2007 and 2008.

Dunbar said Burnet previously worked as a teacher at Columbia International College — a boarding school in Hamilton — as well as public schools in Hamilton, Guelph-Wellington, and Toronto.

Steven Saunders, principal of Columbia International College, told CTV News Toronto that Burnet was hired as a contract teacher at the school in Nov. 2014 and his employment was terminated on Sept. 20.

He said the school “has been advised by local police that the charges against Mr. Burnet are not related to any Columbia International College students, or the College itself.”

He completed a police and vulnerable sector screening prior to being hired.

Dunbar said police executed a total of 14 search warrants and seized more than 100 computers and other devices as part of the investigation.

Investigators believe there may be other victims who have not yet come forward. Dunbar said anyone with information is asked to call Det. Michelle Wiley at 905-546-3856.

OPP Staff Sgt. Frank Goldschmidt says online child exploitation crimes are on the rise in Ontario.

Between 2006 and 2016, Ontario police services have embarked on 35,000 separate investigations into sexual exploitation of children, leading to 12,700 charges laid against 3,665 suspects.

They’ve also located and assisted 1,160 child victims during that time.