A US federal investigation has been launched into policing practices in the city of Minneapolis, a day after one of its former officers was convicted of the murder of George Floyd.

The justice department will look at whether there has been a pattern "of unconstitutional or unlawful policing", Attorney General Merrick Garland said.

It follows national outrage over the killing of Mr Floyd by Derek Chauvin.

The former officer was convicted of all charges against him on Tuesday.

The Justice Department will investigate the policies and operations of the Minneapolis Police Department, Attorney General Merrick B. Garland announced on Wednesday, a day after the former officer Derek Chauvin was convicted of murder in the death of George Floyd in a rare rebuke of police violence.

“The Justice Department has opened a civil investigation to determine whether the Minneapolis Police Department engages in a pattern or practice of unconstitutional or unlawful policing,” Mr. Garland said in brief remarks at the Justice Department.

Attorney General Merrick Garland announced Wednesday that the Justice Department has opened a civil investigation into potentially “unconstitutional” practices at the Minneapolis police department.

The guilty verdict against former officer Derek Chauvin for the murder of resident George Floyd “does not address potentially systemic policing issues in Minneapolis,” Garland said during a Wednesday address.