Federal agents are looking into allegations that high-ranking New Orleans police commanders gave orders after Hurricane Katrina authorizing officers to shoot looters, our partners at the New Orleans Times-Picayune reported today.

Agents have asked for information from New Orleans Police Department Superintendent Ronal Serpas and are asking to interview officers with direct knowledge of the orders, the Times-Picayune says.

The inquiry comes in response to reports by the Times-Picayune, ProPublica and PBS Frontline that described the orders as part of a broader examination of police conduct and shootings of civilians in the days after the storm.

The new inquiry adds to the troubles facing the NOPD, which is already the subject of at least nine ongoing federal investigations. Since February, federal prosecutors have charged 16 current and former cops with crimes allegedly committed after Katrina hurtled the city into chaos. So far, five have pleaded guilty.

We reported Wednesday that several current and former officers recalled a meeting several days after the hurricane at which Warren Riley, then the NOPD's second in command, instructed them and other officers to "take the city back” and “shoot looters."

Riley denied telling officers they could shoot looters. "I didn't say anything like that," he said in an interview for the Frontline documentary, “Law & Disorder," broadcast last night. "I heard rumors that someone else said that. But I certainly didn't say that, no."

The report published Wednesday also said a police captain, James Scott, was captured on videotape by another member of the force telling cops at a morning roll call, “We have authority by martial law to shoot looters.”

Scott, now captain of the department’s special operations division, said he did not recall the incident. His lawyer said that that the entirety of the videotape places Scott’s remark in a different context, but he would not disclose what else Scott said.

It's not clear how broadly the orders concerning looters were communicated, or if they were heard by any of the officers involved in shooting 11 civilians in the days after Katrina.

Some officers told us they refused to pass them on or carry them out. Others say they saw the instructions as a fundamental change in the standards for using deadly force, which allow police to shoot only to protect themselves or others from what appears to be an imminent physical threat.