(Adds police comment)
By Tom Lynn
MADISON, Wis., March 7 (Reuters) - Demonstrators marched on Saturday to protest the police killing of a 19-year-old unarmed black man in Madison, Wisconsin, a shooting that came amid growing scrutiny of law enforcement's use of lethal force against minorities, the poor and mentally ill.
Chanting "the whole damn system is guilty as hell," hundreds of protesters walked peacefully from police headquarters in the state capital to the neighborhood where the young man was shot by police on Friday evening.
They carried a banner reading "Black Lives Matter" that stretched the width of the street and signs that read "Justice 4 Tony" and "5 Shots 5 Times Unacceptable."
The shooting occurred after a police officer responded to calls reporting a man was dodging cars in traffic and had battered another person, Madison Police Chief Mike Koval said.
The officer followed the suspect into an apartment, was struck in the head and shot the teen, who died later at a hospital, Koval said.
Koval said the victim, identified as Tony Robinson Jr., did not have a weapon.
"There's no doubt that we have to be clear about this. He was unarmed," Koval was quoted as saying by the Milwaukee Journal Sentinel.
Spokesmen for the Madison Police were not immediately available to confirm Koval's statement.
Across the street from the house where Robinson was shot, friends and supporters gathered, many in tears.
"I've seen it all over the news, innocent people getting shot by the police. Never once would I have thought it would happen to one of my best friends," said Ramsey Peck, 18, a friend of the victim.
Peck described his friend as "the complete opposite of aggressive."
Alexandra Yahnke, a 24-year-old college student who lives in the neighborhood, said: "This area definitely has some issues with race relations that no one really talks about."
The Wisconsin Department of Justice will oversee the investigation instead of local authorities, under a new law enacted last year.
Last year, the deaths of unarmed black men in Ferguson, Missouri, and in New York City at the hands of police triggered a wave of nationwide demonstrations over excessive use of force by law enforcement. (Reporting by Alex Dobuzinskis in Los Angeles; editing by Ellen Wulfhorst, Andrew Roche, James Dalgleish, Paul Simao, Matthew Lewis and W Simon)