A soldier has been found dead with gunshot wounds in his dormitory at Catterick Garrison in North Yorkshire.
Twenty-three deaths have been reported at the base since 1994
The 24-year-old trainee Coldstream Guard was found at 1645 BST on Monday at Vimy Barracks.
A North Yorkshire Police spokesman said: "Initial witness accounts indicate no other party appears to be directly involved."
Investigations are still continuing and a post-mortem examination was due to be carried out on Tuesday.
An Army spokeswoman said officers were co-operating with the police but could not make any further comment at this stage.
Justin Hugheston-Roberts, a solicitor representing some of the families of men who have died at Catterick, said: "Another tragedy hits Catterick Garrison. What is going wrong at that camp?
"We've got a Defence Select Committee investigation going on at the moment so training establishments are in the spotlight and something else like this happens.
"The problems at Catterick are not going away.
"If this man did commit suicide we need to know what went wrong."
There have been 23 deaths of recruits at Catterick Garrison since 1994.
Some families of those who have died have joined with those campaigning for a public inquiry into the deaths at Deepcut Barracks in Surrey.