U.S. Marshals in Florida used the element of surprise Monday to arrest two men wanted for a weekend strong-arm robbery in Butler.

The suspects — 25-year-old Isaiah J. Tucker and 21-year-old Tyler B. Kern — were nabbed just after getting off an Amtrak train and only hours after Butler police obtained arrest warrants for them.

“They had no clue we were waiting for them,” Barry Golden, senior inspector U.S. Marshals Service-Southern District of Florida, said Wednesday.

Butler police suspect the men, neither with a permanent address, attacked Robert Middendorf early Saturday morning at the alleged victim's auto detailing shop on Pillow Street.

Middendorf told police that he had gone to the 7-Eleven store near his business about 3 a.m. when two men approached him. They asked him if he had a place to stay where they could get out of the cold for a few hours, according to court documents.

He invited the strangers, later identified as the defendants, back to his shop “to stay and have a few drinks with him,” a police affidavit said.

But at some point, Tucker pushed Middendorf out of his chair and held him down, documents said. The suspect allegedly rifled the victim's pockets and took $1,100 and his wallet.

While he struggled with Tucker about 6 a.m., Middendorf said Kern was standing nearby but did nothing to help. After Tucker grabbed the money and wallet, he and Kern ran, documents said.

Middendorf suffered minor injuries.

Investigators later reviewed surveillance video at the 7-Eleven, which showed the alleged victim with the suspects.

Police Capt. David Dalcamo said photographs from the video were posted on the department's Facebook page in hopes of identifying the unknown robbers.

By the end of the day Sunday, authorities had the names of the suspects. District Judge Pete Shaffer on Monday issued arrest warrants for both.

Later Monday, police got an unexpected tip.

“A tipster, based on the Facebook page, indicated the suspects were on an Amtrak train headed to Fort Lauderdale,” Dalcamo said.

The train was to arrive at 6:02 p.m.

Authorities notified the U.S. Marshals Western Pennsylvania Fugitive Task Force, which sent information and photographs of the suspects to the Fort Lauderdale office.

A plan was hatched to place a deputy marshal on board the train two stops or so before it reached the Fort Lauderdale station, Golden said, and confirm Tucker and Kern were on board.

The deputy, in plain clothes, walked past the defendants.

Tucker was dancing, while wearing earbuds and listening to music on a mobile device. Kern was using his cell phone to videotape his alleged accomplice's antics.

“They were acting like they didn't have a care in the world,” Golden said of the suspects.

At the Fort Lauderdale train station nearly a dozen officers with the marshals service, the Broward County Sheriff's Office and the Fort Lauderdale police were poised for the “take down.”

Instead of arresting the defendants on the train, and putting the other passengers at risk, the officers waited for Tucker and Kern to leave.

Moments later, before the two got aboard a curb side bus, the officers swarmed the pair.

“I heard that both of them started crying,” Golden said of the suspects.

The alleged Butler robbers are without bail in the Broward County Jail.

Dalcamo said extradition proceedings are ongoing to have Tucker and Kern returned to Butler County to face charges of robbery and conspiracy.