"We've got some pretty good leads," said FBI spokesman Rich Kolko in Washington.
CLEVELAND -- The FBI is looking overseas for suspects who have phoned bomb threats to more than 24 grocery stores, banks and discount stores in 15 states, including at least six new cases Friday in Ohio.
The callers have threatened to set off a bomb unless store employees wire money to an account abroad. At a Dillons grocery store in Hutchinson, Kan., the caller ordered customers and workers to take off their clothes and threatened to force them to cut off a manager's fingers.
Store workers have been so frightened in at least five cases that they've wired thousands of dollars to the caller.
Police in Newport, R.I., said workers at a Wal-Mart wired $10,000 to the caller. Authorities in Buchanan, Mich., said flustered workers at a Harding's Market sent $3,000 to an account in Paraguay, instead of Portugal as the caller demanded.
The FBI is examining those wire transactions and is working with authorities in Europe to locate possible suspects.
"We've got some pretty good leads," said FBI spokesman Rich Kolko in Washington. "Up to this point these are hoaxes. ... I think folks are catching on and not sending the money."
Four bomb threats were made Friday morning to three grocery stores and a Wal-Mart in northeast Ohio. The threats were phoned in around 6 a.m. to a Wal-Mart and Giant Eagle in Mentor and Giant Eagle stores in neighboring Mentor-on-the-Lake and in Green, south of Akron, authorities said.
The stores were evacuated, but they reopened within two or three hours after police found no explosives.
"We believe these are all tied into the same individual or group of individuals that are doing this all over the United States," said FBI special agent Scott Wilson in Cleveland.
In southwest Ohio, a Bigg's grocery store and a US Bank branch in suburban Cincinnati also received threats Friday.
At US Bank, a man told an employee to have workers sit down on the floor and to wire funds to an overseas account. Another employee completed the transaction, according to the Hamilton County Sheriff's office.
The caller also ordered the worker to put drawer and vault money in bags and go out to the parking lot. Deputies arrived to stop the worker from doing this.
Besides a bomb threat, the caller said he would shoot into the bank if demands weren't met, the sheriff's office said in a statement. He gave the impression that he was watching and knew the movements of everybody inside.
Complicating the investigation are apparent copycat threats. Criminal intelligence analysts are examining police reports to identify similarities in the calls.
"The issue now is determining which ones are tied to the original group of threats," Kolko said. "We still believe they're ongoing."
The FBI believes that among the other stores and banks that have been targeted are a credit union in Albuquerque, N.M.; a Safeway store in Sandy, Ore.; a Wal-Mart in Rio Grande City, Texas; bank branches at Wal-Marts in Salem, Va., and Fairlawn, Va.; a Macey's grocery store in Orem, Utah; a Dillons grocery store in Hutchinson, Kan.; a bank branch in Milford, Conn.; a Vons in Vista, Calif.; a bank in Savannah, Mo.; a bank in Ithaca, N.Y.; and banks in Tampa and Wesley Chapel, Fla.
The FBI also issued guidelines on www.fbi.gov to business owners and suggests that employees get detailed information, asking for specifics about the bomb, what it looks like and when it will explode.
The FBI doesn't offer advice on whether to comply with the caller's demands for money.
"We can't advise companies whether to wire it or not, but we hope they'll be real careful before they hit the send key," Kolko said.
Associated Press writers Dan Sewell in Cincinnati and Eric Tucker in Providence, R.I., contributed to this report.