BOISE, Idaho — Federal agents caught up with a fugitive wanted for trying to kill a New England mob boss more than a decade ago, arresting him at his rural Idaho home where they seized dozens of guns and $15,000, authorities said Wednesday.

Dressed in a yellow jumpsuit and with his hands cuffed behind his back, the man sat at a table in a federal courtroom in Boise and spoke calmly to the judge.

"My name is Enrico M. Ponzo," he said.

After the judge read a long list of charges against him, Ponzo replied: "Not guilty, your honor."

Ponzo, 42, appeared relaxed during his 40-minute court appearance, at times smiling at a handful of friends nearby and exchanging laughs with his attorney.

But the big questions remained unanswered: If he is the mobster, how did he manage to evade capture for so long and how did the Boston native blend in so well into the agriculture towns in southwest Idaho?

To the people who knew him, news that he was a mobster in another life was stunning.

"We’re still in a daze," said Angela Richards, who has known him for more than four years and has gone on camping trips with him. "This is still a really big shock."

Authorities said Ponzo had been living in Marsing, southwest of Boise, under the name Jeffrey Shaw, but they declined to say how the FBI discovered him.

During his arrest on Monday, FBI agents said they seized 38 firearms, cash and a 100-ounce bar of either gold or silver.

Ponzo faces charges from a 1997 indictment accusing him and 14 others of racketeering, attempted murder and conspiracy to kill rivals.

He is charged in the 1989 attempted murder of Frank Salemme. Known as "Cadillac Frank," Salemme is the former head of the Patriarca Family of La Cosa Nostra.

Magistrate Judge Ronald Bush appointed Ponzo a public defender and ordered him held without bail until a detention hearing scheduled for Friday.

Ponzo’s former girlfriend, Cara Lyn Pace, moved out of their home several months ago and is now living with her parents in West Jordan, Utah. Pace’s mother, Linda Pace, declined to comment about Ponzo’s arrest Wednesday.