At the time of writing, 45 people have been killed in protests. Videos below showing how it started and video of the actual assassins.
It is often difficult to understand context when these numbers are given, imagining a violent riot that results in a violent response. But as the videos show, that is simply not the case. The first video shows that this was a tactic to break the protests from a psychological perspective – to leave the protesters in no doubt about the the psychotic nature of their opponents.
Videos from Youtube but H/T to the following blog – worth a read.
More detail on the protests below.
Guardian – Yemen Police Massacre