Captain Ken Masters, who died on 15 October, 2005, aged 40, was a senior military police investigator and commanding officer of 61 Section of the Special Investigations Branch (SIB).

Captain Masters was a high-flying officer who had devoted nearly 25 years to the Royal Military Police. His remarkable dedication and wealth of experience earned him the rank of captain after just 15 years; colleagues believed he had the potential to become a Major.

He was a natural serviceman for whom work was his life. His wife Alison said: "He talked of little else. He lived and breathed it."

He worked in one of the toughest areas of the force, often battling against political pressure and criticism from within the military itself who accused the SIB of being unpatriotic.

But Captain Masters never shied away from the task. According to the Royal Military Police Journal, his investigation into military drug abuse in the 1990s was pivotal to the SIB's move "from a passive, intelligence-gathering unit to a high-profile investigative unit".

Captain Masters was born on 3 January, 1965. The Masters family came from Aberdeen and Captain Masters' father was in the Royal Navy. Many said Captain Masters was born to join the services and he showed early interest, joining the Army cadets aged 12.

In 1981 he became a member of the Royal Military Police. In 1987 he was posted to Northern Ireland as an SIB sergeant. It was here he met his wife Alison; the couple later settled in Portadown and had two girls Kirsten and Hannah.

A devoted family man, Captain Masters took his family all over the world wherever he was posted - Hong Kong, Osnabruck, Bosnia and Belgium - believing every assignment presented opportunities for his daughters.

He even devoted his spare time to the SIB, leading recreational expeditions up Kilimanjaro and organising team skiing trips to Aspen. Time away from the SIB was often spent studying - Captain Masters obtained BSc and LLB degrees from the Open University and was preparing for his maths GCSE in order to help his girls at school.

Having completed a tour in Afghanistan in 2002, Captain Masters received his Iraq papers in November, 2004. He deployed to Basra in March 2005.

Despite his wealth of previous experience, Captain Masters was not prepared for the intense pressure of his Iraq posting, leading the British Military Police's investigative unit in Basra . He told his wife Alison: "Imagine your worst day and multiply it by a thousand."

Under increasing political pressure for rapid results, Captain Masters' team investigated the rising number of abuse allegations against British troops, including the photographed abuse of Iraqi civilians and the death of hotel receptionist, Baha Musa.

Correspondence with Alison revealed that Captain Masters was suffering under intense pressure, manifesting itself in uncharacteristic self-doubt, paranoia, confusion and indecision. He was only managing to get three or four hours of sleep a night and was displaying signs of depression that were noticed by colleagues.

His wife persuaded him to seek medical advice. In his 90-minute session with psychiatrist Corporal Karen Mason, he admitted he was unable to cope with the pressures of the task, but cancelled his second session and was not identified as a suicide risk.

On the morning of Saturday, 15 October, a corporal asked Captain Masters for permission to use his phone, but the Captain was silent, just sitting at his desk and staring into space. He did not reply after the corporal had thanked him for using the phone.

Although the corporal thought this was 'strange', and Captain Masters' noted absence for the rest of the day was out of character, no action was taken until the evening. At 7pm, officers broke into his room in Waterloo Lines to find him hanging.

The inquest confirmed a verdict of suicide. Captain Masters had left two final notes: one to his wife and one to the Army, taking responsibility for his own death.

Although the Captain had been suffering under intense pressure, he was due to go home in five days. His correspondence to his wife on 14 October said: "Not long now though. U and the girls are keeping me going I can tell you. Love you all very much."

Alison suspects his suicide was triggered by an unexpected event in his final days: "The torture for him was over. There was no hint of this and something must have happened."

She remains deeply frustrated by a system she believes failed her husband: "Ken did not suffer in silence. I knew what he was feeling, many of his colleagues knew and medical staff knew - and yet there was no system in place for those concerns to be raised without it damaging his career. That has to change."

Captain Masters was not the first to take his own life at the Basra Branch. In October 2004, at the same base, staff sergeant Denise Rose became the first British servicewoman to commit suicide.