Steven Kirkwood (44) stabbed Mr O’Hanlon four times in the office of HK Autotek garage in Stevenston, Ayrshire, on July 25 last year.
Mr O’Hanlon, who had opened his business Musclebox in Falkirk’s East Bridge only two weeks before the fatal attack, died from massive blood loss.
Kirkwood was originally charged with murder, but the jury at the High Court in Glasgow today unanimously convicted him of the reduced charge of culpable homicide under provocation.
Kirkwood claimed that he had acted in self defence after being assaulted by 45-year-old Mr O’Hanlon and his friend Forbes Cowan (52), a former competitor in the World’s Strongest Man contest.
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Judge Lady Rae said: “This is a very serious offence, although it has been reduced to culpable homicide, particularly in view of his record for violence and the degree of violence that was occasioned in this particular case.”
Lady Rae ordered a background report and a assessment of the risk Kirkwood poses to the public.
The court heard Kirkwood had issued a Facebook challenge to Mr O’Hanlon saying: “If you want to be Johnny Big Baws feel free to come to Hammy’s and see me. I will be there at 12 today.”
The High Court in Glasgow heard that Kirkwood’s ex-partner Eileen Kirkwood was in a relationship with Mr O’Hanlon and they had planned to marry on August 15 last year.
Ms Kirkwood, who has now changed her name by deed poll to O’Hanlon, told the court that as the date of her forthcoming marriage approached, she and Mr O’Hanlon began to get abusive texts from Kirkwood. She admitted that she also sent vile texts making comments about Kirkwood’s new partner Martine Greenan.
Ms O’Hanlon said: “Michael gave me a kiss and a cuddle and said: ‘I won’t be long.’ He said we had to sort things out before the wedding.”
Garage owner Ian Hamilton (40), from Saltcoats, told the court that he saw Kirkwood with a large knife and added: “It was a large Bowie type knife with a six to eight inch blade with a bright coloured handle. A Rambo serrated on one side.”
Kirkwood denied taking the knife with him and claimed he picked it up from the office floor in the garage as he was being assaulted by Mr O’Hanlon and Mr Cowan.
Mr Hamilton said that as he sat in the office having his lunch around middday, Kirkwood walked in. About a minute later Mr O’Hanlon, who was 6ft and 17 stones, turned up with 6ft 4in Mr Cowan
Mr Hamilton said: “Mr Cowan entered the office first and requested for Mr Kirkwood to come outside. There were heated words exchanged between the two of them and Mr Cowan attempted to remove Mr Kirkwood.
“Mr Kirkwood told him, ‘It’s got f*** all to do with you. It’s to do with his f***ing stupid bird.’
“Michael charged through the door with his head down and came at Steven. They tussled, it was a scrummage. It was a wrestle for five seconds.
“Michael backed up out the office stumbling backwards. At that point I saw Steven had a knife in his right hand. I saw blood on the entrance door to the office. I saw blood on the knife.”
When Mr Hamilton went outside he saw Mr O’Hanlon lying on the ground outside badly injured. Mr Cowan described Kirkwood as “aggressive” and said it looked as if he and Mr O’Hanlon were punching each other.
He said Mr O’Hanlon left the office first and he saw Kirkwood had a knife in his right hand.
Mr Cowan added: “Michael wasn’t in a good state. I was speaking to him and keeping a eye on Steven Kirkwood who was still holding the knife. He just stood looking at Michael for three or four minutes then he left the office and walked out.”
Forty-five minutes later Kirkwood confessed that he had stabbed Michael and added: “I think I’ve killed him.”
In evidence, Kirkwood admitted he had stabbed Michael, but claimed he was acting in self defence. He said that Mr Cowan and Mr O’Hanlon were raining blows down on him.
He added: “I felt a jagging sensation on the left side of my back coming round to the front. I thought they were going to kill me. I thought they were trying to stab me.
“At one point I pushed back and I saw a knife on the floor behind my left foot. I grabbed for it and swung it round behind me.”
He told the court he swung the knife about half a dozen times upwards and behind him.
Kirkwood added: “When I left the garage I didn’t know what had happened. Musk was having breathing difficulties. I didn’t think I had struck Musk with the knife.”
Prosecutor Richard Goddard said: “Mr Kirkwood has an extensive record for violence and for carrying weapons. At the time of the offence he was on two bail orders for road traffic offences and under the police and fire reform act.”
Sentence was deferred on Kirkwood until next month. He showed no emotion as he was led away and mouthed “phone me” to family members in the court.