Norman Waller and his neighbour, Peter Fay, clashed with a gang of youths they chased after witnessing them vandalise a car.
Waller, a director of a window company, had armed himself with a chisel, and claimed he lashed out with it after being hit on the head with a bottle. His victim, Terry Malone, 24, of Low Fell, Gateshead, Tyne and Wear, died in hospital from his wounds five days later.
Waller, 34, was cleared of murder and wounding two other youths, who were injured. He was found guilty of an offence of affray. He will be sentenced today.
Mr Fay, 22, a Bradford University student, of Lyndhurst Gardens, Gateshead, Tyne and Wear, was cleared of murder, wounding and affray.
The court was told that Waller, plagued by a series of crimes, snapped when he saw one of the youths trying to break into his neighbour's car late at night last February. David Robson, for the defence, told the jury that Waller did 'no more than any citizen might have done in reasonable self-defence'.
He said he had gone after the gang of youths because police had told him in the past they were powerless to help unless he caught the culprits.
After spotting the gang surrounding his and a neighbour's car he said: 'I thought I've had enough of this. I'm going to catch one of these bastards.'
He said he only armed himself with a chisel from his car when he saw the gang had a Rottweiler dog. 'I had no intention of stabbing anybody. I was very sorry about injuring anybody.'
The court heard that Waller and Mr Fay chased after the culprits and confronted them nearby. Waller denied he was acting as a vigilante and claimed he hit back in self-defence because he was terrified.
He told the jury how his car and his parents' car had been vandalised outside his home at least six times.
He was forced to move his business 20 miles from Low Fell to Fencehouses after it was set on fire, steel shutters were smashed with an axe and raiders dug a tunnel into the building in a robbery bid. Only three of the 20 homes in his street had escaped being targeted by burglars or car vandals.
The prosecution alleged that Waller grabbed one of the youths and held the sharpened chisel to his stomach before striking Mr Malone.
After being arrested he told police: 'I just snapped. I was at the end of my tether with damage to cars and factories. It's just like mob rule. Nothing and no one seems to be safe from them.'
Later he said: 'I wish I'd went to bed and let them wreck the cars. I'm very sorry.'
Waller's wife and two small children have been moved by police to a secret address over fears for their safety.
The mother and sister of the victim collapsed outside court after the verdict and were taken to hospital.Reuse content