Elite soldiers from the U.K.’s Special Boat Service (SBS) are under investigation for the death of a suspected terrorist during a covert operation in Libya two years ago. The incident took place during covert U.K. Special Forces operations in the country. 

According to a Daily Mail report, the elite troops were engaged in a car chase that culminated with their vehicles surrounding the suspect’s. The SBS operatives then opened fire on the vehicle, killing the occupant.

The investigation centers on claims that the suspect could have been arrested rather than killed. The Service Prosecuting Authority (SPA), the military’s legal body, will decide whether to file charges.

The investigation has been underway for months, but no charges have been filed so far. The Ministry of Defence (MOD) has not commented on the case, citing its policy of not discussing special forces operations.

The SBS, which is based in Poole, Dorset, is one of the U.K.’s premier special forces units, primarily recruiting from the Royal Marines. British special forces have been involved in Libya for years, including operations during and after the NATO campaign against Col. Muammar Gaddafi in 2011.

An MOD spokesperson reiterated that U.K. military personnel are held to high standards:

“Action will be taken against anyone failing to meet these standards, including dismissal from service where appropriate.”