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.
Exhibition to celebrate 90 Years of Guernsey's Ambulance Service
Nine decades of Guernsey's Ambulance & Rescue Service will be commemorated this summer.
Guernsey sewage pipe repairs "unlikely to be a quick"
Swimmers in Guernsey may need to avoid the waters around Soldier's Bay for some time.
Guernsey FC to fight for promotion at Victoria Park
The Green Lions are getting ready to host Peacehaven & Telscombe FC in the Southern Combination Football League Play-off Final.
Move to return St Julian's House to Guernsey's emergency shelter
Homelessness charity 'At Home in Guernsey' says it is crucial St Julian's House has free beds for emergency situations.
Jersey and Guernsey included in UK-Gulf trade deal
Jersey and Guernsey have been included in a landmark UK deal with Gulf states that is being hailed a 'significant' boost to the islands' economies.
St Pier says States put investigation before his experience in P&R seat vote
Deputy Gavin St Pier says public perception, not who is best for the job, influenced decisions.
Industry leaders warn against paying Guernsey's under 18s the same as adults
A business group is warned against proposal to pay under 18s the same minimum wage as adults in Guernsey.
Hot, hot, hot, Bank Holiday weekend ahead!
We're set for a sizzling Bank Holiday weekend and start to the school half-term holidays....
