Johannes Mehserle, the former BART police officer accused of shooting and killing an unarmed man New Year's Day, was arrested at 6:20 p.m. Tuesday on a murder charge in Nevada, officials confirmed.

Witnesses say Mehserle, 27, killed Oscar Grant III, 22, at an Oakland BART station in the early morning of Jan. 1, in a shooting that prompted massive protests after videos of the incident surfaced and were shown on television and on the Web.

Mehserle is being held in Douglas County, Nevada, on a no-bail warrant, law-enforcement officials said. Because he was arrested in Nevada, Mehserle will face an extradition hearing before returning to Alameda County, a process which could take at least a few days.

The jail staff reports Mehserle has been cooperative and is housed in a segregated area of the facility and on a "precautionary health and welfare watch."

Alameda County District Attorney Tom Orloff is expected to discuss the arrest further today. Mehserle had been moving from place to place in recent days as he faced numerous death threats. He was reportedly arrested without incident.

Before his arrest, Mehserle was believed to be in the Zephyr Cove area of Lake Tahoe, Nev. Douglas County, authorities said. Oakland Police advised them an arrest warrant for homicide from the Alameda County Superior Court was pending against the former officer.

According to a statement released by the Douglas County Sherriff, authorities in Nevada followed "investigative leads that led them to believe Mehserle was located at the 1000 block of Skyland Drive in Zephyr Cove. Once Douglas County authorities received confirmation the arrest warrant had been issued, officers contacted Mehserle's Sacramento-based attorney, Christopher Miller, and advised him there was an active warrant for his client's arrest."

Miller reportedly called Mehserle, "who in turn exited the residence and surrendered." Calls to Miller were not returned but his office confirmed the arrest.

Skyland Drive appears to be a stone's throw away from Highway 50, and less than a mile from the waters of Lake Tahoe.

"The family will certainly be relieved that the (district attorney) has made some effort to bring him to justice," said John Burris, an attorney who is representing Grant's family in a $25 million claim against BART. "This is terrific. This is a very important step in healing the community."

Mehserle refused to be interviewed by either BART investigators or Orloff's office following the incident. Videos appear to show him shooting Grant as the 22-year-old was facedown on the ground at the Fruitvale BART station.

Mehserle's resignation last week took away BART's best chance at getting a statement from him because Mehserle could no longer be fired for remaining silent.

BART concluded its own investigation into the shooting Monday, but it remained unclear until Tuesday night when he might be detained.

Oakland assistant police chief Howard Jordan said he hoped news of the arrest would calm tensions among the more than 1,000 people expected to protest the shooting today.

"We're hoping that people act civilly and they take this recent action as a sign the (district attorney) was committed to doing (the) job and moving forward with a complete, thorough and unbiased investigation," Jordan said.

On Jan. 7, peaceful protests turned unruly, when a breakaway faction of demonstrators shattered storefront windows, smashed up cars and lit fires in downtown Oakland. More than 100 were arrested.

Earlier Tuesday, Mayor Ron Dellums said he understands the anger people feel, but said taking anger out on people who had nothing to do with the shooting is an injustice in its own right.

"It's fundamentally contradictory to stand up for justice and then dispense injustice," Dellums said. "You can't operate on both planes. You can't walk both sides of the street."