AN arson investigator is retiring after 30 years in the police force.

Detective Constable Graham Thompson dedicated the majority of his career to crime scene investigation and has spent the past five years seconded to the fire brigade's arson investigation unit.

Under his guidance, the unit has witnessed a 12 per cent reduction in arson attacks in the Cleveland area, but he has now decided to call it a day.

He was the first UK officer to join the two-week course at the Bureau of Alcohol, Tobacco and Firearms (ATF) training complex in the foothills of the Blue Ridge Mountains in Virginia, US.

He also spent a week at the ATF headquarters in Washington, DC, getting a vivid insight into how Americans tackle arson and explosives training.

Det Con Thompson joined 33 other officers from all over the US on the course, where he built a bomb hidden inside a bag. The explosive was armed with two sticks of live gelignite and triggered to explode as soon as it was picked up.

When it was detonated, the investigators had to gather the evidence and look for clues, as they would in a real incident.

"Last year, I attended a two-week explosives course and introduced some of the techniques from it into our own procedures," he said.

"I currently run courses at the University of Teesside and I am hoping to become involved in running some of the fire brigade's courses once I retire."