Consider the assassination of Mahmoud Al-Mabbouh. It was intended to look like a natural death, without raising suspicions. To do this, they snuck into his ho

Consider the assassination of Mahmoud Al-Mabbouh. It was intended to look like a natural death, without raising suspicions. To do this, they snuck into his hotel room, injected him with a muscle relaxant, then suffocated him. It took local authorities ten days to realize it was actually a murder. They did eventually figure it out, but I don't think it's hard to imagine intelligence agencies have done similar things before and gotten away with it. In the case of Litvinenko, authorities were pretty sure he'd been poisoned from the onset. The poisoning drew a whole lot of attention that Russia probably could have avoided if they intended to be subtle.