Neighbours have described being woken by screaming, then stepping out into the night to see a young man yelling "He's dead, he's dead".
The man, described as a burglar by police, found the body of a man hanging inside a vacant home in the early hours of Wednesday morning.
People close to the 27-year-old say the man had gone to the house looking for somewhere to sleep on the belief it was empty.
Instead, he entered a lit hallway in the otherwise darkened home and found the dead man.
A neighbour, who did not want to be named, said she heard the young man yelling and went outside to investigate the commotion.
"I come out here and said 'What's happening?' He just came running up and said 'He's dead, he's dead'. I said 'Who's dead?'. He was scared. He was shattered."
"We thought he had moved," the neighbour said of the dead man. "I haven't seen him for about three weeks."
Another neighbour saw the dead man a week ago, but police said he had been dead for no more than a day when the discovery was made.
Hamilton city tactical co-ordinator Senior Sergeant Freda Grace said if the burglar had not discovered the body when he did it could have been days before the man, thought to be in his 40s, was found.
It is understood the young man raced to his mother's house a few doors away and rang police to raise the alarm.
His mother declined to go on record about why her son was in the house, but said he was not a burglar.
Police arrested the man for the break-in and called him a burglar but released him later that morning and Mrs Grace said no charges had been laid.
Mrs Grace said the young man was "known" to police and she hoped the tragic circumstances would alter his behaviour.
Mrs Grace said the whole situation was "incredibly sad".
The death was not being treated as suspicious and had been referred to the coroner.
Several small flowers have been left at the house where the lawns are unmown and junk mail overflows from the letterbox.
The neighbour said the dead man worked long hours and had two children who did not live with him.