Three police officers charged in the killing of two unarmed residents on a New Orleans bridge after Hurricane Katrina and a cover-up that followed pleaded not guilty on Wednesday.

Sgts. Robert Gisevius and Kenneth Bowen and Officer Anthony Villavaso stood before a federal magistrate in green prison garb, shackled at the waist and ankles. They will remain jailed at least until a hearing Friday. A tentative trial date is set for Sept. 13.

Magistrate Louis Moore Jr. read the counts — 13 against Bowen, 11 against Gisevius and 10 against Villavaso. Former officer Robert Faulcon made his initial court appearance Tuesday in Texas, where he was arrested, but has not entered a plea.

The charges against the four carry a maximum sentence of life in prison or the death penalty, although U.S. Attorney Jim Letten said the Justice Department hasn't decided whether to seek the latter punishment.

The family of two victims — Ronald Madison, who was killed, and his brother, Lance, who survived — sat in the front row of the packed courtroom. Gisevius cried quietly as he stood with his lawyer.

"We'll be able to pick this indictment apart," said Frank DeSalvo, Bowen's lawyer. "There is a lot of fantasy there."

Bowen, Gisevius and Villavaso were suspended without pay after the indictments were released Tuesday, NOPD spokesman Bob Young said on Wednesday.

Five former officers already have pleaded guilty to charges they helped cover up the shootings. Prosecutors have said police fabricated witnesses, falsified reports and plotted to plant a gun to make it appear that the shootings were justified.

The shootings at the Danziger Bridge happened Sept. 4, 2005, six days after Hurricane Katrina smashed levees and left the city flooded and in chaos. Bodies floated in filthy flood waters. There were reports of looting and gunshots rang out throughout the blacked-out city.

It was in this backdrop that police, desperate to regain control, were called about 9 a.m. that morning after reports of gunfire at the bridge.

Seven heavily armed New Orleans police officers stormed the bridge. Prosecutors said they shot at the first people they saw, people they say were crossing the bridge to find food.

When it was over, two men were dead and four others lay wounded on the hot concrete.

The indictment claims Faulcon shot mentally disabled Ronald Madison, 40, in the back as he ran away on the west side of the bridge. Bowen is charged with stomping and kicking Madison while he was lying on the ground, wounded but still alive.

Madison's brother, Lance, was arrested and charged with trying to kill police officers. He was jailed for three weeks before being released without indictment.

Bowen, Gisevius, Faulcon and Villavaso also are accused of shooting at an unarmed family on the east side of the bridge, killing 17-year-old James Brissette and wounding four others.

Sgt. Arthur Kaufman and retired Sgt. Gerard Dugue, who helped investigate the shootings, were charged with participating in the alleged cover-up. Charges against them include obstruction of justice.

Kaufman and Bowen "specifically discussed using Hurricane Katrina to excuse failures in the investigation, and thereby to help make any inquiry into the shooting go away," the indictment states.

Kaufman allegedly took a gun from his home and claimed to have found it at the crime scene a day after the shootings, then lied about that gun under oath and in reports, prosecutors said.

Dugue is accused of lying to a federal agent when he said he had no concerns about the truth of the officers' statements.

"In fact, he had many 'red flags' and 'question marks' about the officers' stories, but he reported the questionable information as fact and relied upon it without qualification," the indictment says.

The charges, unsealed Tuesday, are the culmination of a two-year probe by the federal government. An internal police investigation found no wrongdoing by officers. A state grand jury convened to look into the matter charged seven officers with murder or attempted murder, but a state judge threw out all the charges in 2008.