A Canada-wide warrant has been issued for the arrest of a serial sex offender who has breached the conditions of his parole.

Roger Tourigny, 71, is believed to be hiding out in Toronto after fleeing Montreal where publicity about his sex crimes against children has made him more easily recognized by the public, police said.

"We'd like to turn up the heat on this guy because we've got a real concern about him," said an officer investigating the case.

"This guy has been like a ghost to us because we've been on him for a month-and-a-half and we just keep missing him at every turn.

"He knows exactly what he's doing to avoid us."

Tourigny is a seven-time federal offender who preys on children and young teenage boys.

Tourigny is serving a sentence for possession of child pornography. He is subject to a long-term supervision order because of the number of times he has reoffended, police said.

Tourigny has been convicted of possession of child pornography, sexual assault, prostitution, possession and trafficking of narcotics, gross indecency and sexual interference, police said.

He is known to use drugs to lure his victims and frequents Internet cafés and places where troubled teenagers gather.

Police describe Tourigny as being about 5'8", 180 lbs., with brown eyes, grey, balding hair and wearing glasses.

He has scars on his left knee, abdomen and left leg. He also has a tattoo of a native woman on his left arm.

Anyone with information is asked to contact police at (416)808-5900 or Crime Stoppers at (416)222-8477.