A Marines spokesman refused to elaborate when contacted by AFP news agency.
"The chances of success [in Iraq] are essentially zero because the Iraqi people have no voice"
Non Sequitur, Cadiz, Spain
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"We've said all we are going to say about it," he said.
Dela Cruz was one of four marines charged last year with killing civilians in Haditha, 260km west of Baghdad, in November 2005.
Prosecutors alleged that the marines went on a killing spree in the town, shooting unarmed men, women and children after a comrade, Miguel Terrazaz, was killed by a roadside bomb while on patrol.
Defence lawyers said the marines followed established wartime rules of engagement and the deaths occurred after the soldiers became embroiled in a furious firefight with insurgents.
Four other marines - including 3rd Battalion Commander Jeffrey Chessani and Captain Lucas McConnell, neither of whom was in Haditha during the bloodshed - face charges of failing to properly investigate or report the killings.