New York (CNN) -- Citing insufficient evidence, the Department of Justice announced Tuesday it will not pursue federal civil rights charges against police officers involved in the 2006 shooting death of a man hours before he was to be married.
The department issued a statement saying that after a "careful and thorough" review, there is not enough evidence to prove that New York Police Department detectives "acted willfully" when they fired approximately 50 bullets at Sean Bell and his friends the night of November 25, 2006.
Bell, 23, had been at a nightclub in Queens for a bachelor party with friends. He was to wed the mother of his two children hours later.
The shooting occurred after an altercation with the plainclothes detectives. Bell's friends, Joseph Guzman and Trent Benefield, were seriously injured.
None of the three men were armed, an investigation showed.
The shooting sparked street protests, and Mayor Michael Bloomberg called it "inexplicable" and "unacceptable," saying "it sounds to me like excessive force was used."
In March 2007, three of the police officers were indicted on multiple charges.
Detectives Gescard Isnora, Marc Cooper, and Michael Oliver -- who fired his gun 31 times that night, pausing to reload his weapon -- were acquitted of all charges in April 2008
A large protest of the verdict was led by the Rev. Al Sharpton in May 2008. Sharpton, Bell's fiancée and his parents were among more than 200 people arrested.
The Justice Department said it reviewed all the evidence and information gathered by the district attorney's office and police, and took "additional investigative steps" before opting against federal charges.
In the statement released Tuesday, the department said federal criminal civil rights charges hinge on prosecutors establishing that officers deliberately deprived the victims of their constitutional rights, and were specifically intending to do something contrary to the law.
"Neither accident, mistake, fear, negligence nor bad judgment is sufficient to establish a federal criminal civil rights violation," the statement says.
Sharpton released a statement expressing his "extreme disappointment in the decision" and saying he may join with the Bell family in a civil lawsuit "to try and bring some justice."
"Fifty shots on an unarmed man who engaged in no crime is intolerable," he wrote.