A second former New Orleans Police Department officer has been charged in federal court in connection with the Sept. 4, 2005 shootings on the Danziger Bridge. Jeffrey Lehrmann, who left the NOPD to work for U.S. Immigration and Customs Enforcement, was charged last month with concealing a crime, according to court documents unsealed Tuesday and obtained by our partners at the New Orleans Times-Picayune.

Late last year, ProPublica, PBS "Frontline" and the Times-Picayune teamed up to examine a string of violent encounters between police and civilians that occurred in New Orleans during the week after Hurricane Katrina made landfall.

The bridge incident was particularly notorious. Police officers shot six citizens, killing two. Lehrmann, tasked with investigating what happened on the bridge, "participated in the creation of false reports" and provided "false information to investigating agents," according to the bill of information filed by the U.S. Department of Justice.

As the Times-Picayune noted, Lehrmann also plays a central role in another ongoing controversy: While working as an NOPD detective he helped build the case against Michael Anderson, whose murder conviction was overturned recently when a judge found that prosecutors had failed to turn over key evidence to defense lawyers.

Last month, former NOPD Lt. Michael Lohman pleaded guilty to conspiring to obstruct justice in connection with the bridge shootings.