Police say the man, who's not yet been named, died at around 6.40pm on 18 September.
Police say the 66-year-old died in a single vehicle accident on the track to Fort Clonque, at Alderney's south-western tip.
They say as investigations are carried out there will be a police presence in the area and ask people to stay away.
Arrival of mail into Guernsey to take longer as post comes by sea
Incoming mail will now be delivered by boat as the mail plane becomes export only.
Guernsey is "going to be home for the foreseeable future"
Chef Nathan Davies begins island life and says that local produce, like crabs and Guernsey milk, are not just good, they are world class.
Replica Liberation Day medals will be gifted to Guernsey children
Guernsey schoolchildren will receive 'a unique and meaningful gift' to commemorate the 80th anniversary of Liberation Day.
Guernsey sends £50,000 to those affected by Myanmar's earthquake
The Guernsey Overseas Aid & Development Commission is giving £50,000 to Myanmar to help with relief efforts after a 7.7 magnitude earthquake hit the country.
Guernsey PC earns three top accolades for saving a life
PC James De La Mare has received three top honours at the BLE Awards for saving an islander's life whilst off-duty.
Children’s Zone planned for Guernsey's 80th Liberation Day
Guernsey families can celebrate the island's 80th Liberation Day with a vintage fun fair on the Crown Pier.
100 days until Orkney Island Games begin
Athletes from Jersey, Guernsey, Alderney and Sark will be among 2,000 heading to Orkney this July for the 2025 Island Games.
Guernsey hospitality chain buys The Duke of Richmond Hotel
The Little Big Group has purchased The Duke of Richmond Hotel from the Red Carnation Group and says it will update it but pay 'great respect' to its history.
