Karbala attack may have been by Iran forces
The captives may have been killed while the attacks were trying to get to the Iranian border. More details on the attack are given on Roggio's link above. If this is an Iranian operation it makes the recent statements about their activities in Iraq all the more relevant. There is some speculation that they may have been taken as hostages in order to trade for the leader of Iran's forces in Iraq who was captured in the Irbil raid. This evidence suggest an Iranian special forces operation that was unsuccessful in its primary objective.
On January 20th, a team of twelve men disguised as U.S. soldiers entered the Provincial Joint Coordination Center in Karbala, where U.S. soldiers conducted a meeting with local officials, and attacked and killed five soldiers, and wounded another three. The initial reports indicated the five were killed in the Karbala JCC, however the U.S. military has reported that four of those killed were actually removed from the center, handcuffed, and murdered.
The American Forces Information Service provides the details of the attack in Karbala. Based on the sophisticated nature of the raid, as well as the response, or cryptic non-responses, from multiple military and intelligence sources, this raid appears to have been directed and executed by the Qods Force branch of the Iranian Republican Guard Corps. My sources agreed this is far to sophisticated an operation for the Mahdi Army or Badr Corps, while al-Qaeda in Iraq would have a difficult time mounting such an operation in the Shia south. "The Karbala Government Center raid the other day was a little too professional for JAM [Jaish al-Mahdi, or the Mahdi Army]," according to a military source.
This raid required specific intelligence, in depth training for the agents to pass as American troops, resources to provide for weapons, vehicles, uniforms, identification, radios and other items needed to successfully carry out the mission. Hezbollah's Imad Mugniyah executed a similar attack against Israeli forces on the Lebanese border, which initiated the Hezbollah-Israeli war during the summer of 2006.
Westhawk has some interesting comments on what he describes as a new "Phoenix" program in Iraq. That is the name that a very successful program in Vietnam operated under in an effort to destroy the communist leadership.
Belmont Club comments on the old catch and release policy. Why does that sound like a fishing contest?