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.
CI Airports to close early as Storm Goretti approaches
Jersey, Guernsey and Alderney airports will close at 6pm on Thursday evening (8 January) as the islands brace for the peak of Storm Goretti.
Storm Goretti prompts stay-at-home warning in the Channel Islands
Storm force winds with gusts to 90mph and heavy rainfall are expected across the Channel Islands tomorrow evening (8 January).
The Dean of Guernsey to retire later this summer
The Very Reverend Tim Barker has been in charge of the Anglican Church in the Bailiwick for the past decade.
Yacht escorted into St Peter Port after radio contact is lost
The Dutch vessel was on its way to Brest when it lost the use of both its VHF radio and navigation equipment.
Guernsey's animal shelter prepares for injured wildlife from Storm Goretti
The GSPCA is already short of space, with kennels and aviaries turned into temporary pens for sick seals, and the impending storm could mean even more wildlife needing help.
Guernsey hospice struggles with running costs
Les Bourgs Hospice says community support alone may not be enough as care costs and complexities increase.
Body piercing age limit in Guernsey could be lowered to 16
This summer, 16-year-olds in Guernsey may be permitted to get body piercings, with parental permission.
Nighttime cliff rescue in Guernsey
One person is taken to hospital after falling from the cliffs at the Cow's Horn below Fort George.
