ROCKVILLE, Md. (AP) _ Police hunting the serial sniper issued an arrest warrant Wednesday for a 42-year-old man they believe has information about the string of terrifying shootings that have left 10 people dead in the Washington suburbs.

Montgomery County Police Chief Charles Moose said the man, John Allen Muhammad, should be considered "armed and dangerous" and that he was being sought on a federal weapons charge.

He also cautioned that the public should not assume Muhammad is involved in any of the shootings that have stricken the Washington area since Oct. 2.

Moose identified Muhammad as a black male who also goes by the name John Allen Williams. He also said a juvenile may be accompanying Muhammad.

He did not identify the juvenile, but a law enforcement source identified him as 17-year-old Lee Malvo.

A U.S. official in Washington said authorities were looking for two "people of interest," including one who was formerly connected to Fort Lewis, an Army base south of Tacoma, Wash., that provides some of the most intense sniper training in the U.S. military.

A Fort Lewis spokesman said the FBI had asked for help from the base but could say nothing else.

Moose also issued another cryptic message to the sniper:

"You asked us to say 'We have caught the sniper like a duck in a noose.' We understand that hearing us say that is important to you,'" Moose said. "Let's talk directly. We have an answer for you about your option. We are waiting for you to contact us."

The announcement came hours after the investigation jumped across the country. FBI agents converged on a rental home in Tacoma with metal detectors and chain saws, carting away a tree stump from the yard and other potential evidence in a U-Haul truck.

The FBI agents, acting on information from the sniper task force, were seeking evidence related to ammunition, a senior law enforcement official in Washington said on condition of anonymity.

FBI agents also visited Bellingham High School, 90 miles north of Seattle, on Wednesday. Mayor Mark Asmundson told the Bellingham Herald the agents were apparently seeking information on a male teenager who once attended the school and on an older man. He said both left the area about nine months ago.