They said that Ngai's justification for chopping his teacher's head was that he was "trying to get the computer chip out of her head"
Then KGMB interviewed Jackson's brother about this and he said that Jackson Ngai was soft-spoken and wouldn't hurt a fly. He then stated that Jackson had some serious psychological problems recently, which caused him to do something so out of character.
This whole thing remind of an incident 2 years ago, when a mentally unstable man pushed another man into the Ala Wai Canal, resulting in death. That mentally unstable man was reported to be a former scholar-athlete at Punahou High School, known as a friendly guy, but later diagnosed with schizophrenia! I think a similar thing is in play with Jackson Ngai's situation.
Ngai might have to be put into some kind of institution for the safety of the rest of us. However, I think a guy like Jackson Ngai (a very skinny guy) would be super-vulnerable in prison. I'm bigger than him, and even I would be vulnerable there too!