"He gave her $5 and when she opened the cash register, he reached across the counter with his left hand and grabbed the money," while displaying a knife in the other hand, Strong said.
The robber ran out of the store, followed by a witness who got a description of the vehicle and gave it to police.
He was arrested within an hour after the robbery by Frederick County Sheriff's Department deputies who spotted him and gave chase.
Deputy First Class Sherrill Schultz spotted the 1987 blue GMC van eastbound on U.S. 40 west of Shookstown Road at about 9:30 p.m. that was described as the robbery suspect's vehicle, according to Frederick deputies.
Spiegel was arrested after a short chase into a wooded area.
Hagerstown police recovered cash and the knife, deputies said.
Defense attorney Carl Creeden said Spiegel, upset that his business was doing poorly, had consumed a case of beer the day of the robbery.
Spiegel was charged with one count each of armed robbery and theft by Hagerstown City Police and released from the Washington County Detention Center on $50,000 bond.
On Oct. 31, Spiegel failed to appear for trial. Later that day, he was spotted in the 300 block of West Patrick Street in Frederick, police said.
When police approached, the vehicle fled toward Middletown on U.S. 40, reaching speeds of 100 mph, police said.
The chase ended at Spiegel's Lockwood Drive home. Police said he resisted arrest.
Charges lodged against him included fleeing and eluding, reckless driving, driving while intoxicated, driving while revoked, having no license, speeding and resisting arrest.
All additional charges were dropped Thursday in exchange for the plea to robbery.
"I would like to apologize to the clerk. I never meant to hurt anyone," Spiegel said Thursday. "I'm sorry I've shamed my family."