The two men were shot by two men wearing Afghan police uniforms.
The inquest heard an intelligence report that said "insider threat" was difficult to detect. Insurgents and the Taliban used this kind of attack as a tactic and there had been no increase in this kind of threat.
More top news
Following on from the term time holidays row, we look at other rules which have proven controversial.
A man failed not once, not twice but three times when he attempted to raid a bookmakers in Birmingham.
A farm owner has been jailed in south Wales after forcing a "vulnerable" labourer to work for free for 13 years while living in squalor.