The officers encountered Knill, a registered guest at the motel, according to police. Authorities found money that is believed to be the proceeds of bank robberies in Virginia, police said.
The FBI was called in and through a cooperative investigation, Knill was implicated in robberies of banks in Winchester, Leesburg and Richmond, Va., as well as in Boonsboro, police said.
In the Boonsboro robbery, a man entered the Hagerstown Trust branch at 207 N. Main St. at 12:25 p.m. Maryland State Police described him as being slim and dressed all in black, including his hat, hooded sweatshirt, pants and shoes. Police said he also wore black sunglasses.
The robber waved a handgun and demanded money, which he stuffed into the six-pack cooler he carried into the bank, police said.
He left the bank on foot, walked north on Ford Avenue and got into a gray or silver, late 1980s-model Toyota car, police said.
The same branch bank had been robbed on Sept. 13, and two arrests were later made in that robbery.
In another recent bank robbery arrest, a 19-year-old Frederick man was charged over the weekend in connection with a pair of armed bank robberies in Pennsylvania, according to Frederick City Police.
Brent Himes, of 2104 White Hall Road, was in custody in Baltimore awaiting a bond hearing, according to the U.S. Attorney's Office in Baltimore.
Himes was arrested during an investigation of a series of bank robberies, authorities said.
The Frederick, Baltimore and Philadelphia offices of the FBI conducted the investigation with the Frederick police.
The Commerce Bank in Haverford, west of Philadelphia, was held up by a man with a semiautomatic handgun on Dec. 4 and again on Dec. 6, Chase said. No one was injured during either robbery, he said.