The Marines Corps said Tuesday it had dropped all charges against a sergeant in exchange for his testimony against fellow Marines accused of killing 24 civilians in Haditha, the deadliest criminal case to arise from the Iraq war.

Sgt. Sanick P. Dela Cruz had been charged with unpremeditated murder in the death of five Iraq civilians.

Lt. Gen. James Mattis, who announced the deal Tuesday, said the charges against Dela Cruz had been dismissed April 2. Dela Cruz was given immunity in exchange for his testimony, the Marines said.

"Dela Cruz is required to testify," Marine spokesman Lt. Col. Sean Gibson said.

The Marine squad had suffered a fatality on Nov. 19, 2005, when its convoy was rocked by a roadside bomb blast. In the aftermath of the explosion, the troops are accused of killing 24 Iraqis in Haditha.

Four enlisted Marines were charged with unpremeditated murder, and four officers were charged with failing to adequately report the deaths.

Aside from the murder charge, Dela Cruz faced one charge of making a false official statement with intent to deceive. He faced a possible life sentence, dishonorable discharge, dismissal and forfeiture of pay.

Dela Cruz, 24, is the first Marine to make a deal with the government in the case. His testimony will likely form a vital part of the prosecution's case.

The Marine Corps announced the charges in December, but there have been no preliminary hearings and no court dates have been finalized. What would have been the first hearing in the case, for another Marine accused of murder, was recently delayed at the government's request.

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