Mr Hewitt's neighbours were shocked by his death and some residents in the area reported hearing raised voices in the early hours of the morning before his body was found.
"I just heard swearing and yelling while I went out to have a cigarette," a resident told ABC News.
"There was about three of them. I just went inside after that and that was it.
Forensic officers are carrying out a scene examination and streets nearby were closed as police canvassed the area for evidence.
According to his Facebook page Mr Hewitt attended Waiheke High School from 1991 to 1996.
Police could not comment further and said the investigation was ongoing.