A scandal that it's only now a scandal

The ABC reports:

An Australian SAS operator is under investigation for killing an Afghan man his comrades say was an unarmed and intellectually disabled civilian, the ABC can reveal.

The 2012 shooting is known as "the village idiot killing" among the special forces.

The ABC can also reveal the SAS soldier under investigation for this killing is the same man shown shooting dead a different unarmed Afghan man in video footage aired by Four Corners earlier this year.

Known as "Soldier C", he was stood down after the program and is now under investigation by the Australian Federal Police (AFP) for both of the killings. 

ABC Investigations has spoken to two SAS patrol members, witnesses to the newly uncovered killing, who say the disabled man was shot in the back of the head as he was trying to "limp" away.

"Choppers have landed, this guy's ran. Fair enough. We were pretty intimidating," said one patrol member.

"He was obviously intellectually disabled. [Soldier C's] shot this f***er through the back of the head. And I remember it so clearly because his brain literally hit the ground before he did. It was just so unnecessary."

Why isn't it more of a scandal than it seems to be that it has taken 8 YEARS for investigation into a serving SAS member who his fellow SAS members considered  a murderous war criminal??