Who Is Using the 'improvised rocket-assisted mortar' On Our Troops In Iraq?

It is now being called the biggest threat against our troops in Iraq and the group behind it, the ones building it, picking out the targets for it and actually firing it have been nearly impossible to find...until now, perhaps. This really is an excellent article here at Breitbart - I encourage you to read it all. Here's some description of this relatively unpublicized threat to American troops in Iraq:

Maj. Gen. Jeffery Hammond, commander of U.S. forces in Baghdad, called the weapon "the greatest threat right now that we face," and he likened the shadowy group behind it to the American military's elite Delta Force.
The weapon is particularly worrying because it is designed to cause catastrophic damage and cannot be stopped once it has been launched, Hammond, commander of the 4th Infantry Division, said in an interview in his office at this U.S. military headquarters compound just west of the capital.

The 107 mm rockets that are used in the improvised bombs—which some call an airborne version of the roadside bombs that through the course of the war have been the leading killer of U.S. troops—are manufactured in Iran, officials said. But some officers cautioned against assuming Iran is directly involved.
The weapons are launched from small trucks and are fired in multiples of four to nine rockets at a time. The detonation is sometimes triggered by a signal from a cell phone, other times by a washing machine timer.

Basically, the real threat here is that this weapon can be used on a forward base of troops where there could be anywhere from a couple of dozen to close to 200 American troops and it could literally take them all out.
Now, let's look at a new capture by the American forces that might lead to this elite force of jihadists behind this sinister weapon:

U.S. forces detained a man on Thursday who Hammond said could provide valuable insights into the group behind the bombmaking. "We think we have defined the network," he said. He would not elaborate, although other American officers said in interviews that the group is Shiite and may have links to Iran.
"We think we might have picked up a guy that could lead us—could be a big lead in this," Hammond said.

Hammond said the perpetrators are so skilled that he has likened their organization to the U.S. military's secretive and elite Delta Force. He said they have demonstrated an unusual degree of military skill and cunning.
"They don't leave a forensic trail, and that just means we're going to have to work a little bit longer" to eliminate them, he said. "Of everything we've had to deal with here, this is a tough one. They're sort of the Delta Force of this enemy we face out there. They are very good" at covering their tracks, picking out targets and preserving secrecy about their membership and movements.

As I read this article, I couldn't stop envisioning a special force of Shia trained by the Iranians as the ones behind this. I don't buy it that these could be Sadr Militia - they would have been used much more in Sadr City. And some of these tactics mirror those of Hezbollah, who of course is pretty much trained with the Iranian manual. It will be interesting to see if a report comes out soon as to whether this new informant brings us closer to these jihadists - when they are captured or killed, it could reveal Iranian influence in the Iraq War never even imagined before.

'Lob bombs' new biggest worry for US in Baghdad

CAMP LIBERTY, Iraq (AP) - U.S. forces may be close to unlocking the mystery of who is behind a deadly innovation in Iraqi insurgents' weapons, a "lob bomb" now being used in Baghdad to target U.S. and Iraqi combat outposts, a senior American general said Friday in an Associated Press interview.
Maj. Gen. Jeffery Hammond, commander of U.S. forces in Baghdad, called the weapon "the greatest threat right now that we face," and he likened the shadowy group behind it to the American military's elite Delta Force.
The weapon is particularly worrying because it is designed to cause catastrophic damage and cannot be stopped once it has been launched, Hammond, commander of the 4th Infantry Division, said in an interview in his office at this U.S. military headquarters compound just west of the capital.
U.S. forces detained a man on Thursday who Hammond said could provide valuable insights into the group behind the bombmaking. "We think we have defined the network," he said. He would not elaborate, although other American officers said in interviews that the group is Shiite and may have links to Iran.
"We think we might have picked up a guy that could lead us—could be a big lead in this," Hammond said.
It's not clear whether this small group is related to efforts by anti-American Shiite cleric Muqtada al-Sadr to revitalize his Mahdi Army, which had held sway in the Sadr City section of Baghdad until U.S. and Iraqi forces wrested control after seven weeks of fighting that ended in May.
Arguing against a link to such an al-Sadr initiative is the fact that the group that Hammond described has been operating since at least late 2007, although it has become more active in recent months.
The 107 mm rockets that are used in the improvised bombs—which some call an airborne version of the roadside bombs that through the course of the war have been the leading killer of U.S. troops—are manufactured in Iran, officials said. But some officers cautioned against assuming Iran is directly involved.
The weapons are launched from small trucks and are fired in multiples of four to nine rockets at a time. The detonation is sometimes triggered by a signal from a cell phone, other times by a washing machine timer.
Brig. Gen. Will Grimsley, deputy commander of U.S. forces in Baghdad, said in a separate AP interview on Thursday that for lack of a better term he refers to the group as "the evil militia." He said it is small and exhibits a high degree of technical skill in assembling the weapons and executing attacks.