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.
Alex Scott withdraws from England squad
Guernsey's Alex Scott has withdrawn from the England squad.
GST backlash prompts call for calm from Guernsey deputy
Guernsey’s GST vote has sparked anger online, with one deputy calling for calm.
Deputies vote in GST at 3% as part of tax reform package
Policy and Resources' package to raise revenue but ease the burden on the less well-off is passed after six days of debate.
Man charged with murder of Hannah Benfield in Alderney
A man has been charged with the murder of Hannah Benfield in Alderney.
Deputy Inder apologises for raising middle finger to GST protestors
The head Guernsey's Planning Authority has admitted making an obscene gesture at the entrance to the Royal Court.
Guernsey employers face delay over work permits
A 3,800 item backlog is described by the head of Home Affairs as 'sobering reading.'
Chris Kamara launches men's mental health initiative in Guernsey
A campaign backed by football pundit Chris Kamara and aimed at helping men struggling with their mental health has begun in Guernsey.
'Unimaginably painful week' for family of dead Alderney woman
The Cox family has thanked the Alderney community for their support following the suspected murder of 34 year old Hannah Benfield.
