More than three years after the fatal police shooting of Sean Bell, federal prosecutors announced there's "insufficient evidence" to bring a civil rights case against the New York City police officers involved in the case, the Justice Department announced today.

The department conducted an investigation of the events surrounding the Nov. 25, 2006, shooting that resulted in the death of Sean Bell and wounding of Joseph Guzman and Trent Benefield.

In addition to reviewing the original investigative material and court records, federal investigators re-interviewed witnesses and retained an independent ballistics reconstruction expert to conduct an analysis and review the ballistics and reconstruction analyses performed by the NYPD.

"After a careful and thorough review, a team of experienced federal prosecutors and FBI agents determined that the evidence was insufficient to prove, beyond a reasonable doubt, that the law enforcement personnel who fired at Bell, Guzman and Benefield acted willfully," the statement said. "Accordingly, the investigation into this incident has been closed."

The burden of proof is high for a civil rights case against an officer.

Under applicable federal criminal civil rights laws, prosecutors must establish, beyond a reasonable doubt, that a law enforcement officer willfully deprived an individual of a constitutional right, meaning with the deliberate and specific intent to do something the law forbids.

This is the highest standard of intent imposed by law. Neither accident, mistake, fear, negligence nor bad judgment is sufficient to establish a federal criminal civil rights violation, according to the statement.