Start of the fragging season in Iraq?

Here's how you know it's Friday afternoon: the AP reports:

Probe launched into deaths of two officers

BAGHDAD, Iraq — The U.S. military has launched a criminal investigation into this week’s killings of two Army officers at a base north of Baghdad, the military said Friday.
The soldiers were killed Tuesday at 10 p.m. in what the military first believed was an indirect fire attack on Forward Operating Base Danger in Tikrit, 80 miles north of Baghdad, a military statement said.
The slain officers, Capt. Phillip T. Esposito and 1st Lt. Louis E. Allen, were assigned to Headquarters and Headquarters Company of the 42nd Infantry Division, New York Army National Guard.
Esposito was the company commander and Allen served as a company operations officer.
“The initial investigation by responders and military police indicated that a mortar round struck the window on the side of the building where Esposito and Allen were located at the time,” the statement said.
“Upon further examination of the scene by explosive ordnance personnel, it was determined the blast pattern was inconsistent with a mortar attack,” it added without elaborating.
U.S. military officials contacted by The Associated Press declined to comment further on the killings. But the statement said the military’s Criminal Investigation Division is investigating their deaths as a criminal case.
Commanding officer of the 42nd Infantry Division, Maj. Gen. Joseph J. Taluto, extended the military’s “deepest sadness and sympathy for the tragic loss of these two great soldiers.”
The 42nd Infantry Division took over from the 1st Infantry Division in January and is responsible for a vast section of northern and central Iraq.

So it wasn't indirect fire and it wasn't friendly fire. Maybe it was one of those cruel accidents of war. Or maybe not. I'm sure a reasonably robust internal investigation, after a suitable amount of time, will be inconclusive.

*NOTE: MSNBC actually used the term "fragging" on air.