NEW ORLEANS — Attorneys for two of the seven police officers charged in a deadly shooting in Hurricane Katrina’s chaotic aftermath asked a judge yesterday to throw out the murder and attempted murder charges against their clients, saying the officers were promised immunity for their testimony about what happened.The September 2005 shootings on a bridge linking two mostly black neighbourhoods killed two, including a mentally retarded man who was shot five times in the back, and wounded four. Critics have said racism was involved, even though four of the officers, like the two victims, are black.

Ronald Madison, 40, and James Brissette, 19, were killed during the encounter. Police said the officers were responding to a report of other officers being attacked when they came under fire themselves. Police also said Madison was reaching for a gun.

A cheering crowd of more than 200 supporters greeted the officers with hugs Tuesday when they arrived at the city jail to turn themselves in. They will be arraigned Friday.

The officers’ lawyers argue in court papers that the charges should be dropped because they claim District Attorney Eddie Jordan reneged on partial immunity deals his office gave to several officers in exchange for their testimony before a grand jury. Jordan’s office allegedly assured the officers their testimony could not be used against them.

Last Thursday, a grand jury indicted the officers on murder or attempted murder charges.

Bruce Whittaker, an attorney for Officer Ignatius Hills, who is charged with attempted second-degree murder, claimed Jordan’s office forced Hills to give up his constitutional right against self-incrimination by compelling him to testify.

The use of Hills’ testimony was “flagrant, direct and improper,” Whittaker wrote in court papers.

Attorney Frank DeSalvo filed a similar motion yesterday on behalf of Sgt. Kenneth Bowen, who was charged with first-degree murder. DeSalvo said his client initially invoked his Fifth Amendment right against self-incrimination when he appeared before the grand jury in October. Jordan’s office later sought a court order compelling Bowen to testify in exchange for partial immunity.

Officer Mike Hunter Jr., who was charged with attempted first-degree murder, is the only other officer who testified. His attorney, Townsend Myers, was out of town yesterday and did not immediately file a similar motion.

Sgt. Robert Gisevius Jr., officer Anthony Villavaso II and former officer Robert Faulcon Jr., are charged with first-degree murder. Officer Robert Barrios is charged with attempted first-degree murder.

On Friday, the officers’ lawyers plan to ask State District Judge Raymond Bigelow to set or reduce bail for their clients. Bigelow ruled last week that there would be no bond for the four officers charged with first-degree murder. He set bail at $100,000 per count for Hunter, Hills and Barrios.

Six of the officers were suspended without pay pending the outcome of the case. Faulcon has left the department.