Federal regulators are revoking the license of a gun dealer (search) whose store was the source of the rifle used in the Washington, D.C.-area sniper shootings.

The rifle was one of the shop's missing firearms, and the ATF (search) ruling details the store's failure to keep track of its inventory.

Shop owner Brian Borgelt's lawyer, C. James Frush, said he will appeal the ATF ruling.

The ruling gives Borgelt, 38, a grace period to wrap up pending business before his store, Bull's Eye Shooter Supply (search) in Tacoma, is closed. Borgelt was not immediately available for comment.

The store was the source of a .223-caliber Bushmaster AR-15 (search) carbine that was found with sniper defendants Lee Boyd Malvo and John Allen Muhammad when they were arrested in October.

A judge Wednesday ordered a change of venue for the trial of Malvo, moving the case from Fairfax County to Chesapeake, 200 miles to the south. Circuit Court Judge Jane Marum Roush said she feared Malvo wouldn't be able to get a fair trial in the Washington, D.C., suburbs, where the sniper attacks terrorized residents over a three-week period last fall.

Malvo and Muhammad have been linked to 20 shootings, including 13 deaths in Virginia, Maryland, Georgia, Alabama, Louisiana and Washington, D.C.

The rifle was one of dozens of weapons missing from Bull's Eye, said Kelvin Crenshaw, agent in charge of the ATF office in Seattle.

"We expect everyone that has guns, the public and those involved in the business of selling guns, to act responsibly in that ownership and business," Crenshaw said. "We feel what we've done is reasonable and within the bounds of the law to protect the public."

The $1,600 weapon was on prominent display before it vanished from the store in July, investigators determined. The Seattle Times reported in April that Malvo told authorities he stole it.

Besides revoking the license, ATF reportedly has referred its findings to federal prosecutors for a decision on charges against Borgelt.

He also is reportedly being investigated by the Internal Revenue Service, and he and the store are being sued for unspecified damages by relatives of nine sniper victims.