While serving time for sexual assault, Jeffrey Bastien would sneak his cell door open a crack and fantasize about molesting female guards, a dangerous offender hearing heard Friday.

"He did so thinking females would come in and have sex," psychiatrist Dr. Neil Oliver said of Bastien's attempts in 2003 to keep his door open a crack during his stay at Kingston's Regional Treatment Centre of Ontario. Oliver, the chief psychiatrist of the forensic unit at the centre, considered one of the best in Canada for treating the country's worst sex offenders, was the latest in a string of psychiatrists and other mental health professionals to testify before Ontario Superior Court Justice Terry Patterson.

Reading from medical reports prepared at the time, Oliver said Bastien, despite being on medication to lower his sex drive, would be sexually aroused by female guards doing the rounds. Deemed a "sexual deviant," Oliver testified that Bastien told his overseers at the secure treatment facility that he had thoughts of pulling those guards into his cell as hostages to assault them sexually.

"The worst that could happen was a beating," Oliver said of Bastien's thinking at the time. Bastien told the psychiatrist he backed away from the plan over fears it would add to his prison sentence.

For this and other expressed or perceived threats, Bastien was moved on more than one occasion from the centre's third-floor intensive sex offender treatment program to its first-floor acute unit.

Oliver told the court that testing on Bastien showed he was in the borderline range of intelligence, that there was evidence of psychopathy. Oliver said Bastien had a "high potential for criminality" and was a high risk to reoffend.

Even with "multi-faceted intensive treatment," Oliver testified there was no way of knowing "how long he'd need it or whether it would work" in changing Bastien from a continued path of criminal sexual behaviour.

Bastien, whom the court heard has a "prodigious" criminal record, was serving a three-year sentence at the time for the January 2001 sexual assaults on three women around Casino Windsor in the span of 24 hours.

He was convicted in January 2007 for a violent sexual attack on a local high school girl in May 2006, which only ended when the quick-thinking victim managed to dial 911 in the midst of the assault.