NEW ORLEANS (AP) — A former police officer pleaded guilty Friday to trying to help fellow officers cover up the post-Hurricane Katrina shootings on a New Orleans bridge that left two men dead and four others wounded.

Ignatius Hills, 33, pleaded guilty in federal court to conspiracy to obstruct justice and misprision of felony as Lance Madison looked on with members of his family. Madison initially was charged with eight counts of attempted murder and is the brother of Ronald Madison, a severely disabled man who was one of those killed on the Danziger Bridge.

Hands folded in front of him, Hills answered in a calm voice as the judge questioned him about the plea deal, acknowledging that he signed a police department report justifying Lance Madison's arrest, even though he believed Madison was not guilty.

Hills also admitted that he lied when he said that the civilian he fired at "clutched his waistband and turned toward Hills as if grabbing for a weapon."

"At this point we feel very, very good about the progress federal officials are making," said Dr. Romell Madison, the older brother of Lance and Ronald.

Hills was one of seven officers charged in state court with murder or attempted murder. The Justice Department opened its probe after a state judge dismissed those charges in 2008.

Former officers Michael Lohman, Jeffrey Lehrmann, Robert Barrios and Michael Hunter all have pleaded guilty in connection with the shootings.

Marion David Ryder, a convicted felon who was posing as a law enforcement officer on the day of the shootings, also pleaded guilty to lying to the FBI when he claimed a civilian shot at him near the bridge.

Confirming statements by officers who worked out earlier deals, Hills said that he saw numerous civilians lying "bloody and wounded" on the bridge, but "did not see any guns on or near the civilians, and did not perceive any threat from them."

He also reaffirmed the cover-up of the shootings, even attending a meeting with other officers in a gutted police station to make sure their stories were consistent.

The six guilty pleas have been from those involved in the cover-up and appear to lay the foundation for more serious charges against those who actually did the shooting and engineered the cover-up.

"We have not completed this investigation," U.S. Attorney Jim Letten said after the sentencing. "There is a lot of work to be done."

Conspiracy to obstruct justice carries a maximum sentence of five years and a fine of $250,000. The misprision of a felony conviction could draw up to 3 years in prison and a fine of $250,000.

As part of his plea deal, the New Orleans district attorney agreed not to bring state charges against Hills, who also admitted to lying to a state grand jury.

Sentencing was set for Sept. 22.