When I see news of a political activist's slaying, the first thing I look for is how the crime was committed. Often, the modus operandi will have characteristics in common with those from other cases of politically motivated murder that I have investigated in the past. The path to finding answers in some of those cases can be crystal clear, but investigators in others must follow a very murky trail, especially in those carried out by state-sponsored actors. On Nov. 9, the Reuters news service reported on the murder of Iranian political activist Ahmad Mola Nissi, who was shot to death on a street in Amsterdam. Dutch police arrested a suspect who had fled the scene after the attack, but he has since been released from custody.