Those who drove 54-year-old Neil Gordon Watt there on Sunday night fled before they could be interviewed, police said.
Mr Watt’s son Jamie Burns, 26, said he had visited his father at his Mornington home the previous day and was amazed at how healthy he appeared.
"He had a lot of life and colour in him, more than in the last 10 years," he said.
It was in stark contrast to what he witnessed just hours later, Mr Burns said.
"One side of his face was just like all bruised up and the rest of him was covered ... It almost didn’t look like him."
He had heard his father had been "in a fight" and while he had suspicions over who may have been involved, he had no proof, he said.
He knew who had dropped Mr Watt at the hospital and police also had that information, Mr Burns said.
He hoped they would ultimately turn themselves in and explain the circumstances.
"If you were a decent enough human you’d do that in the first place," he said.
Police said last night inquiries were continuing and the death remained unexplained.
Mr Watt was a grandfather of three, had a cousin with whom he was close and a brother who lived in Tauranga, his son said.
And he was widely known around Dunedin.
"You can go around and so many people know him. You walk down the street with him and everyone stops to have a chat.
"He would give the last thing on his back to someone if they really needed it more than him. Even if he didn’t know someone, he’d really help them out."
He had only really known his father, whom he acknowledged had a criminal record, for the past 10 years and would fondly recall their serendipitous meetings around the city, Mr Burns said.
"I would always find him round town when I really needed him. I didn’t even know I was looking for him."
While he struggled to come to terms with the death of his father, he said the loss had given him a keen focus.
"I’m really just having to work on my life a lot and just try and get better every day, make him proud."
