it just shows that the other scenario is at least as probable as the one mentioned above.

Not really - it shows that it is possible to put together a alternative explanation, rather in the same way that it is possible to put together alternative explanations for atrocities apparently carried out by insurgents (the reason I use that word rather than "terrorists" is that anyone who carries out atrocities is by definition engaged in "terrorism", whichever side they are on).

In both cases, deciding that the alternative explanation is "at least as probable", would be going a couple of steps further than is justified. "Cannot be dismissed out of hand" is a more appropriate way to categorise them.

Death squads involving members of the armed forces are a very common phenomenon in many places where there is some kind of civil or paramilitary conflict going on. While it has often been claimed that these have been being some dirty-tricks operation by the other side,    when the facts come out such claims have generally been shown not to h"old water.