The senior military police investigator in Iraq has been found dead at the British base in Basra, the Ministry of Defence (MoD) said.
Military police officers, known as red caps, on parade
Captain Ken Masters was discovered in his accommodation in Waterloo Lines in southern Iraq on Saturday.
The MoD said an inquiry was under way but the circumstances were not regarded as suspicious.
Captain Masters, who was 40 and married with two children, had served with the Royal Military Police since 1981.
The MoD said in a statement: "On Saturday 15 October 2005, the body of Captain Ken Masters was discovered in his accommodation in Waterloo Lines, Basra.
Tension has been high in southern Iraq in recent weeks
"He was Officer Commanding 61 Section, Special Investigation Branch, Royal Military Police.
"He had been responsible for the investigation of all in-theatre serious incidents, plus investigations conducted by the General Police Duties element of the Theatre Investigation Group."
His death will be investigated by the Royal Military Police.
Defence analyst Robert Fox told the BBC Capt Masters was part of "quite a small outfit" and his job would have been quite stressful.
He added: "Quite often they are with British frontline forces when they go on searches and such like, and they would have been doing some of the investigations into cases against British forces on behalf of Iraqi civilians.
Law and order
"It's quite an onerous job. There aren't many of them and there is, I think, quite a lot of stress involved."
The Royal Military Police were called on in major incidents of law and order, he added.
"It's pretty tough for them and it's not very comfortable doing the kind of work they have to do, particularly in the kind of heat we have seen this year."
Capt Masters was commissioned from the ranks in 2001 and served most of his career with the Special Investigation Branch, the MoD said.