A grand jury will not charge anyone in a police blockade that kept hundreds of evacuees from crossing a Mississippi River bridge on foot after Hurricane Katrina flooded New Orleans, authorities said Wednesday. Several hundred people claimed police from suburban Gretna blocked them as they tried to flee New Orleans on Sept. 1, three days after the storm hit. Many of the evacuees, who had been stranded at the New Orleans convention center without food and water, said they were told to cross the bridge to be evacuated from the city, only to be forced to turn around upon reaching the other side.

Police later said they blocked the evacuees because there were no supplies or services for them on the other side of the river. Gretna Police Chief Arthur Lawson also acknowledged that his officers fired shots into the air during the blockade in an attempt to quell what he described as unrest among the evacuees.

The case raised widespread allegations of racism and spurred two marches across the bridge by national civil rights organizations in the months after the hurricane.

Dalton Savwoir, a spokesman for New Orleans District Attorney Eddie Jordan, confirmed that the grand jury declined to bring charges and said the panel was expected to deliver its decision to a state judge Wednesday afternoon.

Gretna police planned to discuss the case at an afternoon news conference.

Written By MICHAEL KUNZELMAN