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.
Remembrance Sunday in the Channel Islands
Today, the Channel Islands will join other nations in remembering those who have fallen in conflicts both throughout history and as recently as today.
'Military people are not good at asking for help... they have to be supported'
A Chelsea pensioner supporting the Royal British Legion in the Channel Islands says they 'do not forget', as Jersey and Guernsey prepare to honour those who made the ultimate sacrifice.
Sark to represent the Bailiwick at the Armistice commemorations
Conseiller John Guille will represent both Sark and the Bailiwick of Guernsey at the annual Cenotaph service in London.
Asian hornet nest found in roof of Guernsey home
A cherry picker was used to access and eliminate the 34th nest found in Guernsey this year.
Bid for extra money for Alderney's air routes fails
Deputies rejected a budget amendment for an extra £360,000 to bolster the Public Service Obligation contract.
Budget freeze on fuel duty in Guernsey
Fuel duty will be frozen for 2027 after deputies rejected Policy and Resources' planned 4.3% rise.
Stay safe celebrating Bonfire Night
If you're marking November 5th with fireworks and bonfires, here are some tips for staying safe.
Guernsey Occupation film production timeline confirmed
Private investors have allowed Under The Watchful Gaze to begin filming in February.
