David James Leblanc is accused of confining and sexually assaulting a teenager on Nova Scotia's South Shore. (RCMP)

David James Leblanc, accused of confining and sexually assaulting a teenager, was flagged as a sexual predator two years ago after he allegedly posted nude photos of two young boys to a website, says Craig Botterill, the lead prosecutor for child pornography cases in Nova Scotia.

But Botterill said it would have been difficult for police to anticipate what is alleged to have happened next.

Leblanc was charged with making and distributing child pornography, sexual assault and sexual interference in the earlier case. The case was postponed but Leblanc was not kept in custody. He was freed on a number of strict conditions, including staying away from computers, children and the places they frequent.

Two year later, Leblanc's child pornography case still hasn't gone to trial because, until recently, he didn't have a lawyer.

Botterill said the 47-year-old is alleged to have posted pictures of two naked young boys on a website where chats, messages and photographs are exchanged.

"Someone in the United States viewed pictures of young boys. One appears to be about one year of age and the other about four years of age, and as a result of that information, Mr. Leblanc was charged with uploading those images of two young boys who were known to him," Botterill said.

The FBI forwarded the complaint to the police in Halifax and Leblanc was later arrested.

Then in 2012 police launched a massive investigation into Leblanc and charged him with sexual assault and forcible confinement of a youth in Upper Chelsea, N.S.

The teenaged boy had chains wrapped around his wrists and ankles, and was wearing only a hooded sweatshirt and a hat when he was found.

Leblanc's co-accused, 31-year-old Wayne Alan Cunningham, was found dead in northern Ontario after a manhunt that lasted several days.

A third man, John Leonard MacKean, was charged on Tuesday with one count of sexual assault.

Behaviour Flagged

"I'm very disturbed by the allegations about what happened to that young man, but given the way the court system works I don't know that anything in this case could have been done any differently to have prevented that," Botterill said.

He said Leblanc was red-flagged as a potential sexual predator against young boys after the child pornography charges in 2010.

"Most commonly, a person is attracted to one age group or another, so in a case where a person's primary interest is young boys … it's not at all common to see them also engaging in sexual offences against, say, a 16-year-old," Botterill said.

Leblanc was scheduled to appear in court on Monday, but it's been delayed so his new lawyer can catch up on the file.