And then on Thursday there was the US army psychiatrist, about to be deployed to Iraq, who allegedly shot dead 13 people and wounded 30 when he went on a rampage at Fort Hood military base in Texas.
It is not known whether there was any connection between the two, in that the US soldier may have been inspired by hearing of the Afghan policeman's actions.
But in any case there is obviously a severe risk from the point of view of the US/UK war machine that the situation will spiral further out of control.
On the one hand, the incidents will have created momentum for a fresh wave of desperate resistance to their military machine that may well lead to further attacks and, at the very least, renewed optimism for their opponents.
On the other, morale amongst US/UK forces, already seemingly at a low ebb, will be plunged into still greater depths, with untold consequences for military efficacity.