Lawyers for a U.S. Marine court-martialed for his role in killing Iraqi civilians in Haditha slammed the international hacking collective Anonymous as cowards on Monday after they knocked out the firm's website and published internal e-mails on the web.

The e-mail and web site of law firm Puckett and Faraj, PC - which represented Marine Frank Wuterich, who pleaded guilty in January to dereliction of duty in the death of 24 Iraqi civilians in Haditha - was forced offline by the internet activist group on Friday and remained down on Monday.

The defense lawyers took to their Twitter account to lambaste the group, saying: Puckett Faraj cyber-attacked Friday by cowards for defending Frank Wuterich from the government the hackers seek to destroy - go figure.

The court-martial of Wuterich, 31, which concluded in late January, was the last in a series of court-martials resulting from shootings and grenade attacks on November 19, 2005, that left two dozen civilians dead in Haditha, a city west of Baghdad that was then an insurgent hotspot.

That incident sparked international condemnation of U.S. troops and added to anger over other abuses by U.S. soldiers or private security contractors during the more than eight years troops spent in Iraq after the U.S.-led invasion that toppled Saddam Hussein in 2003.

Six of the seven other Marines originally accused in the case had previously had their charges dismissed by military judges, while another was cleared of criminal wrongdoing.

The harshest penalty Wuterich faces for his guilty plea is a demotion to the rank of private, the lowest rank in the service, as recommended by a military judge.

Anonymous posted a manifesto on the firm's website - since removed - that decried the brutality of US imperialism and the crooked court systems of military justice.

We want to bring attention to USMC SSgt Frank Wuterich who along with his squad murdered dozens of unarmed civilians during the Iraqi occupation, the manifesto said. Can you believe this scumbag had his charges reduced to involuntary manslaughter and only got away with a pay cut?

Anonymous and fellow group LulzSec have carried out a number of high-profile hacks against companies and institutions across the globe including the Central Intelligence Agency, Britain's Serious Organized Crime Agency, Japan's Sony Corp and Mexican government sites.

The firm's business manager Marcelyn Atwood wrote in an e-mail to her mother in the wake of the hack that this may completely destroy the law firm.

The hacker group said it was angry over the possible life sentence that U.S. Army intelligence analyst Bradley Manning, who is accused of participating in the largest leak of classified information in American history to online whistleblowing site WikiLeaks, faces in an upcoming military court-martial.

Neither Neal Puckett nor his partner Haytham Faraj returned a phone inquiry seeking comment.