Greyhound cannibal interviewer: Vince Li thought he was attacking alien in beheading of Tim McLean (AP) WINNIPEG, Manitoba - A Chinese immigrant who beheaded and cannibalized a fellow passenger on a Greyhound bus in western Canada four years ago thought he was attacking an alien, according to a mental health advocate who interviewed him. In 2009, Vince Li was found not criminally responsible due to mental illness for the death of Tim McLean, a 22-year-old carnival worker who was sitting next to him on a bus traveling near Portage la Prairie, Manitoba. McLean had his eyes closed and was listening to music on his headphones when Li suddenly stood up and started stabbing him. As the bus stopped and horrified passengers fled, Li carved up McLean's body, ate portions of it, and displayed the victim's head to some passengers outside the bus. Greyhound cannibal gets to leave mental hospital Judge: Beheading suspect not responsible Bus beheading suspect pleads insanity After the judge's ruling, Li was placed in a locked wing of the Selkirk Mental Health Centre. Initially, he was not allowed outside, but over the years he has gained more freedom. Last week, a Criminal Code review board decided that Li can start having escorted trips off the hospital grounds and into the nearby city of Selkirk. The ruling sparked renewed outrage from some members of the public, prompting Chris Summerville, head of the Manitoba Schizophrenia Society, to conduct a 45-minute interview with Li last weekend with the hope of shedding light on his progress. Summerville has met with Li roughly every two months over the last four years. " (Li feels) remorse, a degree of humility - I know a lot of people won't believe that - regret and a sense of torment," Summerville said Tuesday. He understands now that schizophrenia is a mental illness which plays tricks on the brain. He knows that the medication works to keep the voices away. Summerville released an edited transcript of the interview to the media Tuesday, in which he and Li discuss the night of July 30, 2008, when Li sat on a bus next to McLean that was traveling on a desolate stretch of the TransCanada Highway bound for Winnipeg. Thirty-seven passengers were aboard the bus. "He was on the lookout for aliens as such, and the voice of God told him that Tim McLean was an alien and he needed to destroy him lest Tim destroy other people," Summerville said. According to Summerville's transcript, Li recognizes that people fear him. I understand people are scared because of my behavior on the Greyhound bus. I am not at risk for anybody. I don't believe in aliens. I don't hear voices," Summerville quoted Li as saying. I take my medication ... everyday. I am glad to take it. I don't have any weird voices any more. Li also told Summerville he would like to be forgiven. I would do anything for (McLean's) family. I would ask forgiveness, but I know it would be hard to accept," Summerville quoted Li as saying. That forgiveness may be a tall order. "I think for the advancement of my own being ... my own soul, I will have to come to a place of accepting," Carol DeDelley, McLean's mother, said Tuesday. But what would be unforgivable for me would be ... to not do anything to try to prevent this from happening again by the same perpetrator. I don't think Vince Li can be trusted to take his medication. DeDelley wants Li kept in a mental hospital permanently, but expects that he will gain more freedom every year until he is eventually released. If he's not responsible for his own behavior, then the state, the government, must step in and be responsible for him for the rest of (his) natural life. Li emigrated to Canada from China in 2001 and became a Canadian citizen four years later.