Trevor Hughes

USA TODAY

ALBUQUERQUE, N.M. — Riot police fired tear gas Sunday as they clashed with protesters, the latest in a series of violent confrontations between officers and residents that include 37 police shootings since 2010.

Protesters took to the streets Sunday afternoon over what some see as persistent police brutality. Albuquerque police have killed 23 people in less than five years, prompting an investigation by the federal Department of Justice. And the FBI is investigating a March 16 fatal shooting of a homeless man in the city of about 555,000. Federal officials say residents worry the police department is abusing its authority and violating residents' civil rights.

"People are concerned, and people want answers. That's why the FBI and the Department of Justice are involved," said Frank Fisher, a spokesman for the FBI's Albuquerque office. "We want to give them answers."

Fisher said the dual investigations are focusing on whether police officers exceeded their authority in the shootings, what's known as "color of law" abuses.

Protester Alexander Siderits, 23, said he was participating because he was "fed up" with how police treat citizens. "It has reached a boiling point, and people just can't take it anymore," he said.

The protest grew violent as night fell. Video aired by KQRE News 13 showed mounted police clashing with protesters, and numerous people being detained by officers after people refused to clear the streets when ordered. Five men and one woman were booked into the local jail on disorderly conduct charges late Sunday and early Monday, jail records show. It was immediately unclear whether any of those arrests were made in connection with the riot, although they were all taken into custody near where it occurred in the Nob Hill section of the city.

Mayor Richard Berry, who said the protests started peacefully then turned to "mayhem," reported one police officer was injured, and at one point protesters trapped police in a vehicle and tried to break the windows, the Albuquerque Journal reported.

The gathering came days after a YouTube video emerged threatening retaliation for a recent deadly police shooting.

The video, which bore the logo of the computer hacking collective Anonymous, warned of a cyberattack on city websites and called for the protest march. Albuquerque police said their site had been breached Sunday afternoon, and police spokesman Simon Drobik confirmed the disruption was due to a cyberattack.

In the shooting on March 16 that led to the YouTube posting, a homeless man was killed on the east side of Albuquerque. The shooting was captured on video and followed a long standoff.

The FBI is investigating that shooting, which outraged the community, said ACLU of New Mexico executive director Peter Simonson. The ACLU was one of the first organizations to call for a federal investigation into Albuquerque police. Simonson said Albuquerque residents believe police operate under a "deeply rooted culture of the ability to use force with impunity."

He added: "Over and over, what we've seen, people who are mentally ill, when they are confronted by the APD, they end up dead," Simonson said. "There is a sense in the community that APD is out of control and there is no city leadership willing to step in and take responsibility."

Last week, Albuquerque police fatally shot a man at a public housing complex. Authorities said he shot at officers before they returned fire.

Multiple messages left with city officials went unreturned Monday, and the police department's Facebook and Twitter pages appeared to have been taken down.

Contributing: The Associated Press