The tip came in on the morning of Thursday, Sept. 1, 2005, as disorder was spreading through the devastated city: Somebody had stolen a Kentwood Springs bottled water truck and was luring in thirsty flood victims with a promise of free water. As people approached the truck, they were being attacked and robbed.

Capt. Jeff Winn, then the commander of the New Orleans Police Department's SWAT team, said the information had come from a fellow officer. "We heard that they had actually shot and hurt somebody and thrown 'em off the Claiborne overpass," Winn recalled later in a taped interview, adding that those involved "were actually raping women."

Winn organized a strike force of SWAT cops and K-9 officers, according to police documents. Officers gathered at Paul B. Habans Elementary School on the West Bank, the SWAT team’s temporary headquarters after Katrina, and then headed to the tangle of highway onramps and exits near the Superdome.

He rolled out in a Ford Crown Victoria with Lt. Dwayne Scheuermann. At about 1 p.m., they found what they were looking for: several Kentwood Springs trucks parked on the overpass. Winn and Scheuermann drove onto a ramp and took up a position overlooking the road while other officers approached the trucks.

The two said they immediately spied trouble: a man with a handgun standing near the back of the trucks. Armed with assault rifles, Winn and Scheuermann fired a barrage of high-velocity rounds. They peppered the torso of Keenon McCann, 28, a tall, beefy 9th Ward native.

There was just one problem: When the officers apprehended McCann, they didn't find a gun, according to NOPD records. The officer who later investigated the incident speculated that McCann threw his weapon off the overpass.

The lack of a handgun raises questions about whether the shooting was proper. Police protocol says that officers should shoot suspects only when they are threatened or they think somebody else is about to be grievously harmed.

McCann survived the shooting and was transported by military helicopter to Baton Rouge General Medical Center for emergency surgery.

He was one of at least 10 people shot by New Orleans police in the week after the hurricane. An examination by ProPublica, The Times-Picayune and the PBS series "Frontline" has found that the NOPD did little to determine whether these shootings were justified, often failing to collect physical evidence, interview civilian witnesses or spend more than a few minutes questioning the police involved.

Scheuermann and Winn declined to be interviewed for this story. NOPD spokesman Bob ***** refused to address questions about the incident, citing the ongoing federal investigation into the department's actions in the days after Katrina. The department also has refused to clear officers to speak about those incidents.

In the aftermath of the hurricane, Winn and Scheuermann were praised as heroes. Ed Bradley told millions of viewers of the CBS program "60 Minutes" that "no one stood stronger" than Winn in those horrific days. Both officers are held up by their colleagues as "real police," officers willing to hurl themselves into dangerous situations.

More recently, however, Winn and Scheuermann have emerged as central figures in the Justice Department probe of possible police misconduct during Katrina. Sources close to the federal investigation say the two officers are the focus of a probe into the death of Henry Glover, an Algiers man who perished at Habans, the SWAT team's elementary school compound, one day after the McCann shooting. Glover's charred remains were later pulled out of a scorched Chevrolet Malibu near the 4th District police station.

Winn, a Marine reservist who saw combat in Iraq, recently was assigned to the criminal intelligence bureau. Scheuermann, most recently assigned to the 1st District, is on sick leave.

"For whatever reason, the government considers them targets but it's unclear what they've been accused of," said Eric Hessler, an attorney representing Winn. "I think it shows they were on the front lines, not in an office or holed up somewhere. They were out there addressing the situations that arose, situations that were thrust upon them."

Hessler said the officers who patrolled the city without leadership or resources are now being unfairly targeted. He blames top NOPD officials for leaving officers in the lurch.

"They didn't have food, water, leadership," he said. "You have guys that stepped up to the plate and did incredible things."

No civilian witness interviews

Typically, when an NOPD officer fires a gun at a citizen, the department's homicide unit examines the incident to make sure the shooting was justified. During separate interviews in November 2005, Winn and Scheuermann told homicide investigators they had acted correctly in shooting McCann because he posed a serious and immediate danger.

Both said they were convinced McCann was poised to ambush the officers who were headed in his direction on the road below.

"I could clearly see that he was armed with a blue steel automatic handgun," Winn said in an interview with an NOPD detective, adding that McCann "appeared to be observing the oncoming officers as if he was laying in wait for them." McCann was planning "to shoot one of those officers as they approached," Winn said.

Scheuermann agreed. McCann was "intent on hurting or killing our police officers," Scheuermann told an NOPD investigator. "I felt we had no choice but to protect our police officers."

The interviews with Winn and Scheuermann formed the core of the investigation, which was led by Detective Sgt. James Anderson, who has since retired. His six-page report does not mention any interviews with police officers who observed the shooting, or civilian witnesses.

The questioning of Winn and Scheuermann was brief, 11 minutes and seven minutes, respectively. Experts who reviewed the interviews as well as Anderson's report say that's not enough time for thorough questioning.

Barbara Attard, a police practices consultant, said she understood it was difficult to perform shooting investigations during the post-Katrina period. Still, she figured the interviews in the McCann case should have been more extensive.

"I would say typically an interview with an officer in an officer-involved shooting should be about an hour," said Attard, who has investigated claims of police misconduct for several California cities.

Attard and other experts faulted NOPD detectives for failing to ask tough questions of their fellow officers or use the conversations to gain a full understanding of the events leading up to the shooting. "I've never seen interviews like this," Attard said. "These aren't probing interviews."

NOPD detectives didn't address some key issues, transcripts of the interviews show. It's not clear, for example, how far Winn and Scheuermann were standing from McCann when they began firing; how many shots they fired; how many rifle rounds struck McCann; or what damage those bullets did to him.

To be sure, Anderson faced significant obstacles as he tried to reconstruct the event two months after it occurred. Police who were present during the shooting didn't interview civilians who saw the incident, or get their names and contact information so interviews could be arranged later.

Hessler said that NOPD leadership ordered officers to keep shooting investigations short, which hampered the followup probes.

"There was a standing order that police shootings were not to be investigated in the manner they normally were," he said. "But I don't think an adequate investigation could have been done. ... They lacked the resources."

The holes in the investigations -- lack of corroboration, specific details and evidence -- are coming back to haunt the involved officers, Hessler said.

"The police officers that pulled the trigger now have to go before grand juries and judges to determine whether they were right or wrong. They are concerned about the lack of corroborating evidence. It's certainly not their fault. It's all rolling downhill."

Anderson's report on the McCann shooting touches only briefly on the central issue: If McCann was armed, why didn't police recover a weapon?

From his research, Anderson concluded that McCann got rid of the handgun before the police could grab him. "It is believed that McCann could have tossed the weapon into the flooded waters" beneath the overpass "or discarded the weapon on the overpass where it was picked up by one of the hundreds of evacuees," Anderson wrote.

Anderson didn't rule one way or another on the shooting, instead stating: "Final disposition of this case will be determined after consultation with the Orleans Parish District Attorney's office."

His report was sent to the DA in April 2006, when the office was held by Eddie Jordan, according to documents from the prosecutor's office. The DA did not act, suggesting that prosecutors found the shooting justified. Winn and Scheuermann weren't punished by the NOPD for the incident, disciplinary records indicate.

Dennis Kenney, a professor at John Jay College of Criminal Justice in New York City, called the NOPD's probe into the McCann shooting superficial. "It's a poor investigation," said Kenney, a former police officer who currently trains Colombian law enforcement agents. The shooting "requires substantially more investigation by the department."

'It all started with the truck'

When McCann's wounds had begun to heal, Corey Smith picked him up from the hospital in Baton Rouge. The two men, best friends, had grown up together in the 9th Ward, their homes a few feet apart.

Smith, who now lives in Texas, said McCann spoke extensively to him about the shooting, particularly in the immediate aftermath.

In the days after the shooting, "Keenon was real distraught," remembered Smith. "He was real shaky, really upset about it. It was anger as well as fear." McCann "had at least five wounds" scattered across his torso, according to Smith, who said he helped change his friend's bandages.

"It all started with the truck," Smith said, recalling what he'd been told. "There was no water so everybody was around the water truck getting water."

Police yelled for the people clustered around the truck to "Halt!" and then, as the crowd sprinted away from the vehicle, Winn and Scheuermann began firing, Smith said his friend told him. He doesn't think McCann was armed: "That's totally bogus," Smith said. McCann was accompanied by his mother and brother at the time of the shooting.

His family declined to comment for this story.

When McCann left the hospital in October 2005, he faced a new problem: the NOPD wanted to jail him for aggravated assault for allegedly threatening the officers with a gun.

A judge issued a warrant for his arrest, and Crimestoppers announced a $2,500 reward for information leading to his capture. In the spring of 2006 the NOPD ran a bulletin in The Times-Picayune saying McCann was wanted by the authorities. Accompanied by an attorney, John Fuller, McCann turned himself in.

McCann was released quickly on his own recognizance. In April 2008, the district attorney's office formally declined to charge him, according to Chris Bowman, a spokesman for current District Attorney Leon Cannizzaro. At the time the case was refused, before Cannizzaro took office, the agency's internal computer system indicated that prosecutors were still waiting for a police report from the NOPD, Bowman said.

McCann, meanwhile, came after the NOPD, filing a civil lawsuit arguing that his rights had been violated. McCann, the complaint states, wasn't armed and wasn't committing any crime when Winn and Scheuermann opened fire.

"After yelling orders for the crowd to disperse, the police officers lowered their weapons and took aim at Mr. McCann," the complaint states. Though McCann hadn't committed any crime, the officers shot him "three times" as his mother watched, causing "injuries to his ribcage, hip, kidney, and shoulder," according to the legal filing.

A court document filed by city lawyers shows the NOPD planned to ask photographer Alex Brandon to testify as a witness to the shooting. Brandon covered the incident while working for The Times-Picayune, snapping the photos that accompany this article. The caption for one of his photos said that Winn and Scheuermann shot at a man who had a gun, though it is not clear whether Brandon saw a gun or was told about it.

Brandon, who now works for The Associated Press, said he couldn't speak about the incident because of the ongoing federal grand jury probe. But in an essay published in 2007 for a journalism magazine, Brandon made an apparent reference to the shooting. He wrote: "I saw a person shot on the interstate by cops who were trying to get their city back."

There is no record that McCann's family ever filed a formal complaint about the incident with NOPD. But plenty of others have complained about heavy-handedness on the part of Scheuermann.

Since 1993, the NOPD's internal affairs unit has investigated 44 complaints of alleged misconduct by the officer, according to NOPD data, making his one of the department's thicker files. While investigators cleared Scheuermann in the majority of those cases, he was disciplined for eight violations, including using excessive force and filing "false or inaccurate reports."

Winn has only one minor violation on his record, dating back to 1994.

McCann's civil case, meanwhile, never went to trial. While it was pending, in August 2008, McCann was murdered. His girlfriend told police he'd been at her house when he received a phone call from someone telling him to "come outside." As he walked out onto Dreux Avenue, somebody shot him to death.

The murder remains unsolved.