A postmortem carried out on Croydon Athletic Chairman David Le Cluse shows he died from a gunshot wound to the head.
The 44-year-old was discovered on Saturday.
He had a licence for a small bore rifle he used in his family run business Merlin Pest Control based in Beckenham.
Paramedics and police rushed to the scene but were unable to save the life of the father-of-two who was pronounced dead at the scene.
The businessman, who owned a pest control business, is understood to have become increasingly distressed about the money laundering allegations directed at the Croydon Athletic's owner Mazhar Majeed, who he counted as a personal friend.
The chairman worked hard to save the Ryman Premier League club from extinction after it was thrown into chaos in August after it became mixed up in the Pakistani cricket betting scandal, with owner Mazhar Majeed alleged to have used the club to launder dirty money from illicit gambling deals.
Mr Majeed has been arrested and bailed by the police.
A police spokesman said: “Police were called at approximately 10:40hrs on Saturday October 2, to garages in Park Gate Road, Sutton following reports of a seriously injured man.
“Police and London Ambulance Service attended and found a man suffering a gunshot wound to the head. He was pronounced dead at the scene.
“A postmortem examination held on Monday October 4, at St Helier Hospital, Carshalton, gave cause of death as a gunshot wound to the head.
“Officers from Sutton are investigating. Inquiries into the circumstances are ongoing.
“An inquest will open in due course.”
Fans and friends have spoken about their devastation at the death of the popular chairman.
Former manager Tim O’Shea said: “It was a massive shock and it's a very sad loss. He did everything in his power to save the club.
“He was a great guy and I am deeply saddened. My thoughts are with Julie and the kids, I am just devastated.”
A statement from the club reads: "Croydon Athletic are deeply shocked and saddened by the sudden tragic death of their chairman, David Le Cluse, on Saturday October 2.
"Our thoughts and prayers are with David's wife and children, and we would ask everyone to respect their privacy at this devastating time for them."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here