Family and friends of the Scottish accountant are still struggling to come to terms with his decision to walk calmly into the Aberdeen gunsmiths and then end his life by blasting himself in the head with a shotgun.
Mr Munro, an associate partner with Hall Morrice, an Aberdeen firm of chartered accountants, committed suicide at teatime on Monday after he called at Anderson Guns, in the Hardgate, shortly before closing time and asked to look at one of the weapons for sale.
It emerged yesterday that the 40-year-old father of two killed himself when the owner, Neil Anderson, was briefly distracted by a telephone call.
As Mr Anderson answered the call, Mr Munro calmly slipped a cartridge he had smuggled into the shop into the gun and put the barrel to his head. Mr Anderson's wife was also in the shop at the time.
All gun shops operate a strict policy of not allowing customers access to weapons and ammunition at the same time.
But Mr Munro, a keen clay pigeon shooter, managed to load and fire the shotgun in the few seconds it took for the shop owner to answer the phone.
The busy gunsmiths, close to the city centre, reopened for business yesterday for the first time since the tragedy.
Mr Anderson declined to comment on the shooting. He said: "I am not going to speak to anybody. Nobody is going to hear what happened, how it happened, except Grampian Police, myself and my wife - end of story."
Mr Munro, who lived with his wife, Sandra, and their two children in the leafy suburb of Milltimber, had been due to return to his desk at Hall Morrice's offices in Queen's Terrace on Tuesday morning after a long weekend.
He had told colleagues he was taking the Monday off to spend time with his wife and children, who were off school because of a mid-term break. On Saturday, he was one of the spectators at Pittodrie Stadium for Aberdeen's Premier League match against Falkirk. He is understood to have attended the game as a corporate guest of a major bank.
One of those who watched the match with Mr Munro described him as "first-class company". He added: "He was the life and soul of the party at the football and afterwards."
A spokeswoman for Hall Morrice said yesterday: "Mr Munro was not under investigation at work for anything at all. He has never been investigated at work for anything untoward.
"Everyone is just completely shocked. There is no indication at all as to why he would have done this."
She added that some of his colleagues at Hall Morrice had met Mr Munro at Pittodrie on Saturday.
"His colleagues had a table at Pittodrie and go to the football regularly for corporate entertainment," she said.
"He [Mr Munro] was in good spirits. Everyone is at a complete loss as to what happened. It is just very, very tragic and there doesn't seem to be any explanation at all as to why he might have done it."