U.S. Sen. Patty Murray (D-Shoreline) and five colleagues are demanding more information about past investigations at the Tacoma gun shop linked to the rifle used in the East Coast sniper attacks.
The Bushmaster .223-caliber rifle vanished from Bull's Eye Shooter Supply without a paper trail, apparently along with hundreds of other weapons.
Agents from the Bureau of Alcohol, Tobacco and Firearms have been at Bull's Eye for a week, reviewing its paperwork and reportedly failing to find documents on 340 guns.
"We are greatly concerned ... by reports that the rifle linked to the sniper attacks may have been illegally transferred by a federally licensed firearms dealer ... who has reportedly been under investigation by ATF for several years," the senators wrote Thursday in a letter addressed to Treasury Secretary Paul O'Neill, who oversees the ATF.
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"We would appreciate clarification of a number of issues related to this case so that Congress may take appropriate steps to ensure that federal firearms laws are being adequately enforced."
The letter seeks information on past audits at Bull's Eye, what violations were identified and whether agents ever tried to yank the store's license.
Also Thursday, law enforcement officials said they had linked the Bushmaster to a Sept. 23 killing in Baton Rouge. Authorities have already laid charges in Alabama and connected it to two shooting cases in Tacoma, all with ballistics evidence.
In at least three other states, police have identified specific murder cases they believe could be linked, but with little real evidence so far.
The task of determining the spree's full scope is daunting.
The accused snipers, John Muhammad and John Lee Malvo, lived in or drifted through many states and the Caribbean.
The sniper demanded $10 million - a twist that further expands the range of possible criminal methods and motives.
Attorney General John Ashcroft said Thursday that investigators also are still exploring whether other people took part in the crime spree.
Police in many states have reopened old files to check for elements common with the sniper case. That three-week killing field left 10 dead and three wounded and brought charges from Virginia, Maryland and federal prosecutors.
State and local police have reported checks for any related cases in at least Washington state, Oregon, California, Arizona, Louisiana, Alabama, Tennessee and Michigan.
In the Louisiana case, beauty supply worker Hong Im Ballenger was killed during a Baton Rouge robbery. There is suspicion the rifle used to shoot her in the head also might have been involved in another shooting in the city that did not kill anybody.
Muhammad grew up in Baton Rouge and also visited relatives with Malvo there in the weeks before the sniper attacks.
Baton Rouge police also are seeking DNA samples from each man to check for links to yet another case - the serial murders of three women between fall 2001 and last summer. One woman was strangled, one stabbed and one had a slit throat.
Authorities, however, say they are still leaning more heavily toward a white man, as predicted in an FBI profile, as a more likely kind of suspect in those murders. Muhammad and Malvo are black.
In Michigan, Lansing police were following up with the sniper task force to check on any connection to the shooting death of Bernita White at a zoo entrance in June 2001.
She was shot by someone hiding behind a fence about 200 yards away. The capital-area sniper also fired at long range.
"It's something we're looking into, but it's nothing formal," said police Lt. John Parks in Lansing. "You can't ignore it."
There is no known evidence that Muhammad and Malvo were in Michigan. However, a friend of Muhammad's, who helped buy the car allegedly used in the sniper case, was arrested in Michigan as a material witness.
In Oregon, where Muhammad once served in the National Guard, state police glanced back at several dozen sniping cases over the last decade or so, without finding any matches, spokesman Andy Olsen said.
In Montgomery, Ala., the Sept. 21 robbery attempt left one woman dead and another wounded outside a liquor store.
Tacoma police have linked Muhammad and Malvo to the February murder of 21-year-old Keenya Cook, who possibly was shot out of fury toward her aunt for taking sides with Muhammad's ex-wife in a custody dispute.
Police suspect the pair in connection with shots fired at Temple Beth El synagogue in May, an incident in which no one was hurt.