James McGowan,58, was found guilty on Tuesday of repeatedly stabbing Owen Brannigan in a house in Coatbridge, Lanarkshire, in November 1999.
McGowan - who fled the murder scene to go back to his home in Australia - blew a kiss to his son Ryan who was sitting in the public benches of court room three at the High Court in Edinburgh.
McGowan Snr then placed his hand on his heart and looked at his son and other family members. The gesture came just a few moments before security officers placed handcuffs on his wrist and took him down to the court building cells.
The emotional gesture came just a few minutes after a jury at court delivered their verdicts in the case. They had taken 24 hours to consider their decisions.
McGowan, who was extradited to stand trial in Scotland from his home in Adelaide, was also convicted of head butting a cousin of Mr Brannigan’s at a Coatbridge social club.
The attack on Thomas Duggan came just a few hours before he inflicted 11 stab wounds on Mr Brannigan, who was once married to McGowan’s sister Carol.
On Tuesday, jurors broke off from their deliberations shortly before 11am and came back to court to return a unanimous verdict of guilt to the assault charge.
The jury of eight men and seven women returned a majority verdict of guilt to the murder charge.
Judge Lady Scott deferred sentence on McGowan for the court to obtain reports about his character.
But she warned him that he’ll be spending the rest of his life behind bars.
She told McGowan: “The law states that there is only one sentence which I can impose in a case with this charge - that is life.
“However, I must also fix a punishment part to your sentence - the punishment part is the sentence you must serve before you become eligible for parole.
“I will therefore defer sentence and you will be brought before me again at a hearing next month.”
The decision of the jury came on the seventh day of proceedings and has brought to McGowan’s flight from justice to an end.
The court heard how McGowan and his wife had emigrated to Australia from Scotland in 1980. The boilermaker had returned to his family in Coatbridge several times.
Jurors also heard that the was bad feeling between the McGowan family and Owen Brannigan.
Mr Brannigan, who had served in the Royal Navy, had been married to McGowan’s sister Carol but they divorced in 1984 after nine years of marriage.
The court heard that McGowan had the belief that Mr Brannigan had raped a woman - police investigating the case found no proof of this ever happening.
However, prosecutors believe that this mistaken belief was Mr McGowan’s motive in attacking Mr McGowan.
He returned to Scotland in November 1999 after his mum Frances died in Coatbridge. But when he was back home, McGowan committed the assault and murder on November 28 and the early hours of November 29.
In the hours before the murder, McGowan assaulted Thomas Duggan - Owen’s cousin - by head butting him at the Kirkshaws Social Club in Coatbridge. Mr Duggan needed hospital treatment after the attack.
The court heard that McGowan then started looking for Owen Brannigan around Coatbridge. He found him at a house in the town which was occupied by Thomas Stewart.
McGowan then repeatedly stabbed Mr Brannigan and fled. Hours later, McGowan turned up at the offices of British Airways in Gordon Street, Glasgow,.
The court heard that McGowan turned up five minutes after the store opened. At 9.05am he told travel consultant John Slack that he needed to change his December 10 1999 return flight to the “next available flight”.
He left Heathrow on December 3 1999 and flew to Perth, Western Australia - a total of 1,699 miles from his home in Adelaide.
Police in Scotland immediately identified McGowan as the number one suspect in the case. They contacted the Australian authorities in a bid to bring him back to Scotland.
However, Scottish prosecutors decided there wasn’t enough evidence to bring him to court. Scottish detectives travelled to McGowan’s home in Australia in March 2001.
However, he declined to be interviewed and Scottish police were unable to do anything further.
The break through in the case came in 2012 when McGowan’s marriage fell apart. He telephoned On the Line - a mental health charity - and confessed what he had done in Scotland.
Telling counsellors that his sons Ryan and Dylan were playing professional football in Scotland, McGowan also confessed that he was a murderer.
Jurors heard him say: “Once you’ve crossed the line and you jump back.. you know you can always go across the line.
“Some people can’t go across it and I know I went and done it and it’s a frightening thing - a frightening thing to do with.
“You go ‘Jesus, I can’t kill people. But I did.”
Australian police learned about the phone calls and contacted Scottish police. He was arrested and extradited to Scotland.
During a week long trial, McGowan denied all wrong doing. He blamed Mr Stewart and said he was the man who murdered Owen Brannigan.
Prosecutors couldn’t find any evidence to link Mr Stewart to the crimes.
In the end, the jury agreed with the submissions made by prosecution lawyer Alex Prentice QC that McGowan was a murderer.
After returning the verdict, McGowan’s solicitor advocate Murray Macara QC said he would reserve his position until the sentencing hearing.
Speaking after the case, Owen’s sister Bernadette said the verdicts had brought her family closure. She also said she hoped that her family and the McGowan family could reconcile.
She added: “I just want to move on from this and be rid of the animosity between both families. It has torn us all apart.”