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.
68% of Guernsey post boxes set for removal
Guernsey Post proposes to reduce the number of roadside post boxes to 45, in response to a significant decline in usage.
Guernsey joins calls for peace in Gaza
Guernsey's Chief Minister has written to the UK's Prime Minister to express support for ending the war in Gaza.
Guernsey's population may be 3% smaller than stated
Issues with data in the Rolling Electronic Census mean the number of people leaving the island may have been over estimated.
Cimandis to pull food wholesale operation from the Channel Islands
The Channel Islands' largest food wholesaler is pulling out of both Jersey and the Bailiwick of Guernsey.
New External Relations Lead selected amid Guernsey Police investigation
Deputy Steve Falla has been selected as Guernsey's new Lead for External Relations and Constitutional Affairs.
Vale Douzaine to host two emergency sleeper pods for Guernsey homeless
The Guernsey homelessness charity Caritas has submitted a planning application to install two emergency sleeping pods in the Vale Douzaine car park.
Guernsey deputies express dismay over famine in Gaza
Policy and Resources is asked to formally write to the British government over the deepening humanitarian crisis.
Guernsey education experts help shape new National Writing Framework
Two members of the States of Guernsey's Education Office joined an expert sector panel to improve how children are taught communication skills.
