Authorities were searching Monday for man suspected of holding a 73-year-old woman and her husband hostage at their home, then forcing her to try to rob a bank with what she thought was a bomb strapped to her ankle.The woman, Betty Davis, told employees at the bank in Fayetteville about the device, and authorities were able to safely evacuate the building on Monday before a bomb squad could remove it from Davis' leg, police said. Authorities were testing the device to see if it really was dangerous.Davis told police that a man had been holding her and her husband captive in their Washington County home, and sheriff's deputies dispatched there found her husband tied up but unharmed. Authorities didn't release Davis' husband's name.The couple's pickup truck was missing, and Fayetteville TV station KHOG reported Monday evening that sheriff's deputies found an abandoned truck believed to be the couple's.The couple could only vaguely describe the suspect as a white male of an indeterminate age who was wearing blue jeans.Washington County sheriff's Lt. Emily Augustine said Monday night that investigators believe the couple's story."The evidence we have supports the witness statements so far," Augustine said.Fayetteville police spokesman Sgt. Craig Stout told the Arkansas Democrat-Gazette that Davis was cooperative and didn't show any signs of deception.Fayetteville is in northwest Arkansas and is about 140 miles northwest of Little Rock.