Ian Bush, 59, has undergone the court-ordered assessment in connection with an alleged attack on 101-year-old Ernest Côté in December 2014, where he's accused of leaving the veteran bound with a plastic bag over his head.
Bush remains in custody on charges of attempted murder, robbery, forcible confinement, breaking and entering, two counts of using a credit card obtained by crime, plus 11 charges for possessing illegal weapons.
Earlier this week, sources told CBC News that police have also investigated a link between Bush and the triple homicide of a retired judge, his wife and a neighbour.
Police sources said DNA evidence was found at the scene of the 2007 slayings of Alban Garon, his wife Raymonde, and their friend and neighbour Marie-Claire Beniskos. The three were also found with bags over their heads.
2 warrants linked to 2007 homicides
This week, Bush's lawyer, Geraldine Castle-Trudel, said police executed two search warrants related to her client. One allowed police to take a DNA sample from Bush and a second allowed officers to enter Bush's family home in the east Ottawa suburb of Orleans, according to Castle-Trudel.
The 11 weapons charges originate from when officers executed the warrant at Bush's home in January.
Police have been investigating a link between Bush and the unsolved triple homicide for several weeks, sources also confirmed to CBC News, and Bush is the "prime suspect."
None of the allegations has been proven in court and no charges relating to the unsolved homicides have been laid.
Castle-Trudel has questioned the release of information pertaining to a link between the unsolved homicides and her client, saying she is "really upset" about the leak.
"If the police are going to charge my client with something, fine, go ahead, charge him," she said earlier this week.