NEW ORLEANS (AP) — A Louisiana State Police trooper who witnessed part of a deadly encounter between police and residents on a New Orleans bridge after Hurricane Katrina recalls ducking for cover because he thought he and other officers were under fire.

But the trooper, Michael Baron, testified Tuesday at a federal trial for five current or former New Orleans police officers that he never perceived a need to use deadly force on the Danziger Bridge because he didn’t see anybody posing an “imminent threat.”

After ducking for cover at the top of the bridge, Baron drove three officers to the west side, where former officer Robert Faulcon shot and killed 40-year-old Ronald Madison, a mentally disabled man.

Prosecutors say Faulcon shot an unarmed man in the back. Baron said he wasn’t looking at Faulcon when he opened fire.

Police shot and killed two people and wounded four others on the bridge on Sept. 4, 2005, less than a week after the storm smashed levees and plunged the city into flooding and chaos.

Prosecutors say the officers shot unarmed people crossing the bridge in search of food, but defense attorneys claim police were shot at before they returned fire.

Baron said he had been escorting a group of construction workers on Interstate 10, which runs parallel to the Danziger Bridge, when a police officer flagged down his convoy and asked for help responding to a report that an “officer was down” on the bridge. Baron said he followed the officer to the crest of the bridge, where he saw several officers on foot.

Gunfire erupted as he rolled down the window to ask, “What’s going on?” Baron testified. He heard the bullets hit something metallic, but Baron said he couldn’t tell where the shots were coming from or if they were incoming or outgoing.

After he ducked, Baron said, an officer pointed toward the west side of the bridge and said, “Those are guys shooting at us down there.”

“Let’s get ‘em,” Baron recalled an officer saying.

Baron drove Faulcon and two other officers down the bridge, chasing after three men. He saw Madison wobbling as he ran, with his right hand tucked underneath his left arm, and what appeared to be a bloodstain on his shirt.

“Did you see any need to shoot that individual?” prosecutor Theodore Carter asked.

“At that particular moment, no, sir,” Baron said.

Moments later, however, Faulcon shot Madison with a shotgun. Baron said he heard the gunshot and saw Madison fall to the ground, but he didn’t see Faulcon fire because he had “tunnel vision” while he apprehended another man on the bridge.

After the shooting, Baron said he approached Sgt. Arthur Kaufman, who was assigned to investigate the shootings, because he thought he might have to give a statement.

“He said, ‘If you didn’t shoot, I don’t need you,”’ Baron testified.

Kaufman is charged with participating in a cover-up to make the shootings appear justified.

In other testimony Tuesday, former NOPD officer Kevin Bryan said a fellow officer used a racial slur in explaining why he fired at a teenager fleeing from the shootings.

Bryan, who left the department about a year after the 2005 storm, recalled asking fellow officer Ignatius Hills why he fired two shots at the back of a 14-year-old from the rear of a rental truck that police drove to the bridge in response to a distress call. Hills responded that he tried to “pop a round off” at the black teenager, referring to the youngster with a racial epithet, Bryan testified.

“It wasn’t that he was scared for his life or anything like that,” said Bryan, now a Plaquemines Parish sheriff’s deputy.

Hills, who is also black, pleaded guilty to a conspiracy charge and testified last week as a prosecution witness. Hills said he fired two shots at the boy’s back “out of fear,” but missed. He didn’t mention using a racial slur against the boy, Leonard Bartholomew IV.

After Hills shot at the fleeing teen, Bryan chased Bartholomew down the bridge with his gun drawn. But he said he didn’t shoot at Bartholomew because he didn’t pose a threat.

Bryan said he slapped Bartholomew with an open hand in the “heat of the moment,” immediately feeling “horrible.”

Bartholomew was arrested but freed within a matter of hours. His parents, sister and cousin, Jose Holmes, were wounded but survived the shootings. Holmes’ friend, 17-year-old James Brissette, was shot and killed on the east side of the bridge.

Bartholomew sobbed on the witness stand Tuesday when he recalled visiting his family in the hospital for the first time, more than a week after the shootings.

“Everybody else had to go through all this pain, and I’m walking around,” he said.

Bartholomew said nobody in his group that morning was armed or did anything to provoke police. They were crossing the bridge in search of food at a grocery store when police opened fire without issuing any warnings, he said.

“I thought this was a big mistake,” he recalled.