DOJ to investigate Baltimore police
Freddie Gray seen in a video being arrested by Baltimore officers (Screenshot)

The US Justice Department will conduct a federal probe into Baltimore's police department following riots triggered by the death of a black man under police arrest, the Washington Post reported.

Attorney General Loretta Lynch could make the announcement as early as Friday, the Post said, citing two law enforcement officials.

A spokesperson for the Justice Department had said Wednesday that Lynch was "actively considering" a civil rights probe into the city's police department following a request from Mayor Stephanie Rawlings-Blake.

The mayor asked for an investigation that would look into whether the city's police department "has engaged in a pattern or practice of stops, searches or arrests" that violated residents' legal rights.

On April 12, Freddie Gray suffered a serious spinal injury while in the back of a police van. The 25-year-old died from the injury a week later, setting off riots in Baltimore.

The incident occurred at a time of exacerbated racial tensions in the United States, following the death of a number of unarmed black men at the hands of white police.

One of the most prominent cases was that of Michael Brown, an 18-year-old who was fatally shot in Ferguson, Missouri last year, sparking extensive and sometimes violent protests across the nation.

A federal civil investigation into the incident led to a damning report on racism and biased law enforcement in the St Louis suburb's police department.

"When there are allegations of wrongdoing made against individual officers and police departments, the Department of Justice has a responsibility to examine the evidence and, if necessary, implement changes," Lynch told a Senate subcommittee Thursday, according to the Post.

"The situation in Baltimore involves a core responsibility of the Department of Justice -- not only to combat illegal conduct when it occurs but to help prevent the circumstances that give rise to it in the first place," she said.