Greg, who spoke on condition his surname was not used, told the Otago Daily Times Luke James Lambert (42) had been living in a vehicle and occasionally sleeping rough around the city earlier this year.
Lambert, whom he met at East Otago High School as a 12-year-old, was well enough to play cricket, and appeared revitalised.
"All in the team including myself had noticed a change in him — for the better. This season he'd come back with a new energy," Greg said.
"Then six weeks later I heard about a stabbing spree at Countdown and I shuddered ... Then that night at home a mate rung me and said, ‘Tell me that wasn't Luke at Countdown’. Before he got the words out I had a chilling feeling."
This week in the High Court at Dunedin Lambert pleaded guilty to four counts of attempted murder and the horrifying details of the incident were revealed.
He spent half an hour in Countdown Dunedin Central on the afternoon of May 10, buying a pie and a soft drink but had insufficient funds for the two cans of beer.
The defendant complained to an associate in the Octagon he had been denied medication and that "someone is going to get it".
When he returned to the supermarket just minutes later he removed two knives from shelves and went on a frenzied attack, severely wounding four people.
Remarkably, the victims survived.
Lambert refused to explain his actions to police and Greg was bereft of answers.
"This was not the Luke I knew. What had happened to my friend in six weeks?"
They played rugby and cricket together in Waikouaiti and Lambert lived in the township for some time, he said.
But the stability did not last.
Greg said Lambert later sold up and moved to a "rundown wee house" in Shag Point where he "lived a bit of a hermit’s life".
The men stayed in touch and the friend recalled sporadic visits where he would head out to the rugged coastal spot to drop off groceries.
Lambert then made a more drastic change, buying a camper van, which marked the beginning of life on the road.
Greg said the man would travel between Dunback, Geraldine and Dunedin, spending a few months at each location before moving on.
But when the van "rusted out" and his mother died, Lambert had spent the last couple of years living in her car in Dunedin.
He often parked up near Moana Pool, Greg said, and complained about several incidents during which teenagers had tormented him.
But he told the ODT he had never seen Lambert lash out.
"He's never really shown violence in front of me. I've seen him punched and he walked away rather that fight. He knew Tai kwon do," Greg said.
"He was always honest and fair. I've seen him ripped off and just accept it and let it go."
Lambert was remanded in custody following his guilty pleas this week and will be sentenced in May next year.
