Bulford, UK—A court-martial over the deaths of three aspiring SAS reservists has begun.

Two special forces instructors face jail over the incident. The accused, for PERSEC reasons only identified as 1A and 1B, are charged with a negligence whilst performing their duties. The persecution, in particular, focuses its case on their lack of health and safety standards.

The fatal exercise took place In July 2013. It was a 16-mile speed march across the treacherous Brecon Beacons in Wales. Although the march was 16 miles on the map, in reality, it was closer to 20 miles, given the anomalous terrain, which is specially chosen by the UKSF for its arduousness. The SF candidates had eight hours and 45 minutes to complete the exercise.

Two of the territorial soldiers, Lance Corporal Craig Roberts and Lance Corporal Edward Maher, died from heatstroke. The third, Corporal James Dunsby, succumbed to extensive organ failure two weeks later.

The SF instructors were respectively the training officer in charge and the chief instructor of the training event. Before the march took place, they had signed the risk-assessment form.

“The charge against the defendants is that they were negligent in their duty to plan and conduct the exercise safely in relation to the well-known risk of heat illness. The risk to the candidates wasn’t properly appreciated or assessed and, in this regard, there was a negligent failure with planning and preparation,” said Louis Mably, the Queen’s prosecutor.

The three unfortunate soldiers weren’t the only casualties of the exercise. Multiple other soldiers went down with heat-injuries. In total, 41 regular and 37 territorial soldiers took part in the speed march.

During the march, SF candidates carried a rucksack weighing close to 60 pounds and a dummy rifle weighing seven pounds.