-LRB- CNN -RRB- -- A man charged in the beheading death of his seatmate on a Greyhound Canada bus last summer is not criminally responsible because he is mentally ill , a judge ruled Thursday , said CNN affiliate CBC News . The ruling means that Vince Weiguang Li will be hospitalized at a psychiatric facility until he undergoes a review by Manitoba 's Criminal Code Review Board in 90 days , CBC said . `` The goal of criminal law is to punish criminals , not persons who have a severe mental illness , '' Manitoba Court of Queen 's Bench Judge John Scurfield wrote in the ruling , CBC reported . However , the ruling angered relatives of Tim McLean Jr. , 22 , who died on the bus July 30 . `` The bottom line is , he is getting away with murder , '' Vana Smart , McLean 's sister , told CBC . Watch how the verdict angers the victim 's family '' Prosecutors told reporters Thursday they had no choice but to ask the judge to find Li not criminally responsible . `` This was justice because the correct conclusion was reached , '' prosecutor Joyce Dalmyn said , according to CBC . `` Mr. Li is a schizophrenic . Mr. Li had a severe mental disease . Mr. Li , in my opinion and in the opinion of the psychiatrists , had no idea what he was doing was wrong . '' Li , 40 , was charged with second-degree murder in McLean 's death . A witness on the bus , which was headed from Edmonton , Alberta , to Winnipeg , Manitoba , said a passenger repeatedly stabbed and then decapitated McLean as horrified passengers watched . Just before his death , the victim had been sleeping with his head leaning against the window . `` There was a blood-curdling scream . I was just reading my book and all of a sudden I heard it , '' Garnet Caton , who was sitting in front of the two men , told Canadian TV at the time . She said the knife-wielding man shouted at the other passengers to get off the bus , and they did . `` Me and a trucker that stopped and the Greyhound driver ran up to the door to maybe see if the guy was still alive or we could help or something like that , '' Caton said . `` And when we all got up -LRB- to the door -RRB- , we saw that the guy was cutting off the guy 's head . '' Thirty-four passengers were on the bus . Police said at the time it was unclear what prompted the attack . Witnesses said Li 's weapon was a large butcher knife . Li was arrested after an hours-long standoff , during which he remained in the bus with McLean 's body . Police said he was seized after he broke a window and attempted to jump from the bus . `` Mr. Li is also a victim here , '' said Ruth Ann Craig of the Canadian Mental Health Association , according to CBC . `` What 's going to happen to Mr. Li is not a cakewalk . '' He will be housed in a locked psychiatric ward , Craig said , while he undergoes assessment and treatment to determine whether he is a risk to himself or society . But Tim McLean 's mother , Carol deDelley , said she will fight to change the law regarding these types of crimes . `` I 'm going to do everything I can to make a change here , '' she said , CBC reported . McLean 's father said he is also disappointed with the ruling . `` We 've all lost a family member , '' he told CBC . `` This is n't the right result . ''