By Julia Edwards
WASHINGTON (Reuters) - The U.S. Justice Department will open an investigation into the Chicago Police Department after protests over how it handled the case of a black teenager shot by a white police officer, a person familiar with the matter said on Sunday.
The "patterns and practices" investigation will determine whether the department systematically violates constitutional rights, according to the source, who spoke on condition of anonymity. They would not elaborate on the investigation.
The civil probe follows murder charges being filed against the police officer in the October 2014 killing. The shooting was caught on videotape, which was not released until the charges were filed last month.
Officer Jason Van Dyke was charged with first-degree murder in the death of 17-year-old Laquan McDonald, who was shot 16 times. Shortly after that, the city released a patrol car video of the shooting. Van Dyke fired all of the shots.
Protests erupted afterwards in the nation's third-largest city, culminating in the firing on Tuesday of Police Superintendent Garry McCarthy by Mayor Rahm Emanuel. Critics of the mayor and the local prosecutor have complained that it took too long for the McDonald tape to be released and for charges to be filed.
The release of the video comes at a time of heightened debate in the United States over police use of lethal force, especially against black people. Over the past year, protests against killings of unarmed black men and women - some videotaped with phones or police cameras - have rocked a number of U.S. cities.
A patterns and practices investigation does not criminally charge individuals, but often results in a consent decree between the police department and Justice Department to agree to new practices and accountability measures.
The investigation was requested by the Illinois attorney general.
(Reporting by Julia Edwards; Writing by Doina Chiacu; Editing by Jonathan Oatis and Alan Crosby)