A 68-year-old man, who once worked for the Department of National Defence, is facing child pornography charges again.

The former nuclear physicist was arrested after a search warrant was executed in the area of Yonge Street and Sheppard Avenue East on Thursday.

Police allege a man engaged in multiple “sexually explicit” conversations with a boy through social media. The man allegedly sent the boy abusive images and directed him to send child pornography images of himself, according to investigators.

Officers said the man used the names “TomLarkin789” and “btnevans” while communicating through various social media sites.

On Friday, police said they believed there may be other victims.

Blair Thomas Newton Evans, of Toronto, was arrested in connection with the investigation. He is now facing fourteen charges, none of which have been proven in court.

According to CTVNews.ca, Evans has faced multiple child porn charges over the past 20 years.

He was arrested in Ottawa in 1996 on child pornography possession charges, and later convicted. He was again arrested on similar charges in 2002 and convicted.

In 2004, Evans was arrested on child pornography charges once again, and received a 47-month sentence.

Most recently, he was arrested in 2009 at a Toronto public library branch for accessing the Internet, disobeying his 2005 probation conditions. He was subsequently convicted of failure to comply with probation.

Evans was scheduled to appear in court on Thursday.