The "friendly-fire" incident in the inhospitable desert between the nondescript towns of Ajdabiya and Brega, in eastern Libya, has exposed huge deficiencies in the rebel army.
It has also, not for the first time, raised questions about the decision-making process of Nato pilots and planners.
Rear Admiral Russ Harding, from Nato Joint Force Command, was absolutely right when he said it was hard to tell rebel fighters apart from Colonel Muammar Gaddafi's troops - after all, they generally wear the same uniforms and have similar weaponry and vehicles.
Nor is the battlefield - the front line - a clearly defined space with one side lining up to the west, the other to the east.
So, ask rebel supporters in Benghazi, amid the confusion, why did Nato pilots elect to launch rockets against targets they could not positively identify?
But Nato is caught between a rock and a hard place.
Only two days ago, rebel leaders were urging the alliance to significantly increase its air strikes, not only against Col Gaddafi's tanks and offensive weapons, but against his supply-lines and positions around towns like Brega, Ajdabiya and Misrata.
Sometimes, Nato and the sophisticated bombers flying high above the desert get it horribly wrong.
But it is a mistake for which rebel commanders in Benghazi and on the ground must share the blame.
The Nato statement that the alliance had not been told of a rebel advance to the front with tanks and rocket launchers contradicted an earlier line from Benghazi that Nato had, indeed, been informed.
The problem for the rebel leaders is that throughout this conflict they have demonstrated an alarming level of incompetence and lack of organisation.
Most of their fighters, apart from the few former regular troops, have little experience holding and firing basic assault rifles, let alone powerful rockets or heavy weaponry.
There is also an obvious lack of military leadership at the front - every day enthusiastic rebel fighters charge off into battle, under no clear command and control structure, and every day they come back again when they come under fire from Col Gaddafi's much better trained and equipped troops.
There clearly needs to be better basic co-ordination on the ground.
Military experts say the rebel army should change its tactics - dig in defensive positions, co-ordinate their attacks and conserve ammunition by not firing aimlessly in the general direction of Col Gaddafi's troops.
Crucially, Nato needs to know who is who and what is where on the ground.
Using "spotters" in the desert or in the air would be a start. Rebel troops would also help their own cause by making themselves and their vehicles clearly identifiable from the air.
If that does not happen and there are more tragic incidents like that on Thursday, the relationship between Nato and the rebel leadership will break down, seriously undermining their ability to take on and defeat Col Gaddafi.