The U.S. Department of Justice will not bring charges against Baltimore police officers over the fatal injury of a black man in custody in an incident that stoked tensions between African-Americans and law enforcement, federal officials said on Tuesday.

A Justice Department criminal civil rights investigation into the death of 25-year-old Freddie Gray has found "insufficient evidence" for any charges, the U.S. Department of Justice said in a statement.

"The Justice Department remains committed to investigating allegations of excessive force by law enforcement officers and will continue to devote the resources required to ensure that all serious allegations of civil rights violations are thoroughly examined," the statement said.

Gray was arrested in April 2015 and suffered a fatal spinal injury while being transported in a police van. The largely African-American city erupted in rioting on the day of his funeral, leading to a curfew and deployment of National Guard troops.

His death was one of several incidents in recent years in U.S. cities, such as Ferguson, Missouri, that sparked a nationwide debate about the use of excessive force by police, especially against black men.

Baltimore prosecutors charged six police officers in Gray's death, but none was convicted. Public disciplinary trials are scheduled for five of the officers.