SAGINAW, Mich. — No civil rights charges will be filed against a group of Michigan police officers in the shooting death of a homeless, mentally ill man, federal officials said Tuesday.Milton Hall was shot 11 times during a July 2012 confrontation with officers in a Saginaw parking lot. Police have said the 49-year-old Hall was holding a knife and moving toward an officer and police dog when he was shot."Federal authorities have determined that this tragic event does not present sufficient evidence of willful misconduct to lead to a federal criminal prosecution of the police officers involved," the U.S. Justice Department said.No local or state charges were filed in the case.The Justice Department's Civil Rights Division, U.S. attorney's office and the FBI reviewed results of a criminal probe by state police, Michigan's attorney general and Saginaw County prosecutor as part of their investigation. Evidence reviewed also included witness statements and videos from police car dashboard cameras and cellphones.It was determined "that the evidence in this case is insufficient to prove, beyond a reasonable doubt" that Saginaw officers "willfully shot Hall for an unlawful purpose," the release stated."Even if the officers were mistaken in their assessment of the threat posed by Hall, this would not establish that the officers acted willfully, or with an unlawful intent, when using deadly force against Hall."Nearly 50 rounds were fired by six officers.Hall's death prompted a number of protests in Saginaw, about 80 miles northwest of Detroit.His mother, Jewel Hall, told The Associated Press that the FBI delivered a letter to her early Tuesday about the decision not to file charges.Jewel Hall, 82, said that does not mean the case is over."The letter gave excellent facts that can be used as we pursue justice for my son," she said from her New Mexico home.