The US Justice Department is to investigate whether the police department in Baltimore engages in routine bias or excessive force, according to US media reports.
The inquiry was requested by Baltimore's Mayor Stephanie Rawlings-Blake after the death of Freddie Gray, a black male who died while in police custody, sparking large scale riots and protests.
US Attorney General Loretta Lynch is expected to formally announce the investigation possibly as early as today.
A spokesperson for the Justice Department said on Wednesday that Ms 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 12 April, 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.
