On YouTube There is a 7 minute interview with the man who was sitting directly in front of the killer and victim (who were in the last seats in front of the bathroom) who said that Li (the killer) was sitting toward the front and only moved to the aisle seat next to the victim after the last stop - which was about 20 minutes before he went crazy and stated stabbing the man sitting next to him in the window seat.
The man who was killed was evidently NOT asleep the entire time Li was sitting next to him, but was texting with his family and girlfriend until just minutes before Li started stabbing him. There has been speculation that Li is a paranoid schizophrenic and something that the victim did (texting, wearing headphones, playing with his cell phone) made him believe the victim was an alien or evil and MUST be killed (or beheaded). Who knows, but there are several interviews with passengers on YouTube and obviously Li went crazy, but in a calm and robotic way - complete dis-association with the victim as a human (he could have been having visual hallucinations as well) and seeing the entire event as a triumph over an "evil thing" - which is a hallmark of severe mental illness. Li may (or may not) have thought the other passengers were also "aliens" or "evil" - it is probably good he was contained safely. It seems Li was not sociopathic but that there was something much deeper - a complete disconnect from reality, like severe schizophrenia where you only hear the voices in your head telling you to "kill the alien".
BTW, not all schizophrenics talk BACK to the voices audibly, some have the entire conversation in their heads or even on paper. I can tell you from personal experience that sometimes PS's do NOT mutter or talk back to the "voices" and that they can appear totally normal and then 5 minutes later be completely disassociated from reality and everything around them. For some reason KNIVES are a favorite weapon of theirs, not sure why? When I 1st saw this I felt immediately that it was severe, untreated, delusional, paranoid schizophrenia - it has most of the hallmarks - and the poor victim was just in the wrong place doing something totally innocent when this guy went totally off into the freak-zone thinking he had to protect himself and possibly "the world" from the evil "thing" sitting next to him. I am sure that the bus ride (in the dark an a desolate highway) also had something to do with setting this in motion and sometime during the stop, Li started to see the victim as a threat, one he had to behead to "save the world" because only HE could see the "evil one".
The killer has NO RECORD of anything but it is reported that in recent months he had begun to act increasingly strange and take off on unplanned trips and telling his wife and employer totally different stories - the wife hadn't seen him in days (since before the weekend) , the boss saw him last on Mon or Tues - he told everyone one something different - family emergency, job interview. He was obviously losing touch with reality as there was no job interview and no emergency. Once the illness and stress becomes too much, sometimes the PS begins to wander - looking for or hiding from the evil, the aliens, whatever. And he isn't talking becuase the "voices" are telling him they "captured" him and he must never tell what he "knows". Until he is properly medicated, he will not speak or help in his own defense - he cannot. The mental assessment will find he is almost catatonic in his current state, he will not speak....at all. This man beheaded and mutilated another human being and never spoke a single WORD the entire time.
There is a LOT of material on YouTube - a 1st hand account from the primary witness to the entire event.
My Opinion