Demonstrators sit on a railroad track in front of an Amtrak train during a march against the New York City grand jury decision to not indict in the death of Eric Garner in Berkeley, California December 8, 2014. [Photo/Agencies]

REVIEW OF POLICE KILLINGS

New York State Attorney General Eric Schneiderman on Monday said he was seeking the power to investigate all police killings of unarmed civilians in the state.

It remained unclear whether New York Governor Andrew Cuomo would grant Schneiderman such powers. Like the Democratic mayor of New York, Cuomo has tried to walk a fine line -- expressing concern about the grand jury's decision not to charge an officer in Garner's death while not alienating the police.

On Monday US Attorney General Eric Holder, whose office is investigating the Garner case, announced changes to federal law enforcement guidelines intended to set an example for local police, according to a Justice Department official.

In Cleveland, Samaria Rice, the mother of a 12-year-old African-American boy shot dead by police in November, told reporters she was seeking a conviction.

Her son, Tamir Rice, was shot near a recreation center while carrying a pellet gun that was a replica of a real gun. The boy's family has filed a federal civil rights lawsuit against the city and the two officers involved, one who shot Rice on Nov. 22 and one who was driving the police car.

"Tamir was a bright child, he had a promising future and he was very talented in all sports: soccer, basketball, football," Rice said. "He was my baby."