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.
Investigation into fire in derelict Forest building
A fire broke out in a disused building in the Forest.
Guernsey's Animal Shelter warns of myxomatosis outbreak in wild rabbits
The advice to pet owners is to have their rabbits vaccinated against the disease.
Home of Guernsey Football celebrates its one year anniversary
Guernsey’s Victoria Park is celebrating its first anniversary with a weekend of football.
Renaissance 'masterpieces' on display in Guernsey
"Remarkable artworks" from the Renaissance are currently on display in St Peter's Port.
Guernsey's airline reacts to reduced demand because of Iran attacks
Aurigny is rescheduling some flights between mid April and June and will levy a £2 fuel surcharge per sector.
Survey reveals scale of dissatisfaction with off-island travel
A new survey reveals just how dissatisfied Channel Islanders are with the cost and reliability of travelling off-island.
Two youngsters questioned by Guernsey Police after fire at Leale's Yard
Fire crews spent one and a half hours putting out the blaze in a derelict building.
Prominent Guernsey consultant cardiologist suspended by the GMC
The MSG says Dr Dean Patterson is no longer a partner but that he is fighting his temporary medical suspension.
