premise: Sergeant Alistair Slater, MM (25 July 1956 – 2 December 1984), was a British Army soldier who served in B Squadron, Air (7) Troop, 22 Special Air Service (SAS), who was killed on 2 December 1984 while on operations against the Provisional Irish Republican Army in Kesh, a village in County Fermanagh in Northern Ireland.
hypothesis: Slater was killed by the Provisional Irish Republican Army
reason: While it is certainly implied he was killed by the Provisional Irish Republican Army, we are only told that Sergeant Slater was killed in Kesh while on operations. It could have been friendly fire. It could have been a medical incident (stroke, bp, infection, etc). We are not told how he died.