The grand jury essentially is disputing the official police description of an Sept. 4, 2005, incident, the New Orleans Times-Picayune reported.
The shooting grew out of a report that snipers were shooting at rescue workers near New Orleans' Danziger Bridge six days after Hurricane Katrina struck the Gulf Region.
The shooting incident involving police officers left two people dead and four seriously wounded. One man was shot seven times in the back.
The New Orleans Police Department said the seven officers acted appropriately.
"We cannot allow our police officers to shoot and kill our citizens without justification like rabid dogs," District Attorney Eddie Jordan said. "The rules governing lethal force are not suspended in an emergency. Everyone, including police, must abide by the law of the land."