PORTLAND — A man who lost part of a finger as he was assembling pipe bombs will be held without bail pending trial because he poses a threat to the community and might not show up for trial, authorities say.

Robert Infante, 47, was in U.S. District Court in Portland today where he waived a probable cause hearing and a detention hearing. Infante and his publicly appointed federal defender, Hilary Billings, said the government would have prevailed in its effort to show there was reason to arrest him and to hold him without bail.

Infante was arrested last week at Southern Maine Medical Center in Biddeford after he blew off part of his left middle finger while in the basement of his house on Avery Road in Alfred. He said the injury was the result of a gas explosion.

Firefighters checking his house discovered several pipe bombs, marijuana plants and guns, which he is barred from possessing because he is a felon, according to court papers. The State Police bomb squad also found five pipe bombs in his car, which he had used to drive himself to the hospital after the explosion.

Infante has a history of federal convictions including for possessing explosives and possession of firearms by a felon.

Infante appeared in U.S. District Court in Portland today wearing a bandage around his hand and his arm was in a sling.

Infante did say he plans to challenge the evidence against him, saying investigators gathered the evidence illegally.

“I just don’t understand how they were able to run right into my house without a warrant,” Infante told U.S. Magistrate Judge John Rich. Infante contends that the initial inspections of his house were illegal and that it was information gleaned from them that formed the basis for the search warrant that was obtained later.