By Jay Croft

CNN

(CNN) -- A former neo-Nazi who had recently converted to Islam is charged with murdering two of his roommates for "disrespecting" his new faith, police in Tampa, Florida said.

Devon Arthurs, 18, confessed in detail on tape to killing Jeremy Himmelman, 22, and Andrew Oneschuk, 18, police said.

The killings came to light after Arthurs, armed with a semiautomatic pistol, held three other people hostage Friday evening at the Green Planet Smoke Shop, near the apartment he shared with Himmelman, Oneschuk and Brandon Russell, 21.

Arthurs told his hostages he was "upset due to America bombing his Muslim countries," the affidavit states.

Arthurs surrendered to police after a brief negotiation, shouting "Allah Mohammed!" while being walked to a patrol car, police said.

"I had to do it," he said, according to the police document. "This wouldn't have had to happen if your country didn't bomb my country."

Officers asked Arthurs if anyone else was hurt.

"The people in the apartment," he replied, according to the police report. "But they aren't hurt. They're dead."

Three hostages, then two bodies

Police took Arthurs to Tampa Palms Apartments, where they found Russell crying outside the apartment door. Russell, who authorities say serves in the Army National Guard, was dressed in "full US Army camouflage," police said.

"That's my roommate (Russell)," Arthurs told police. "He doesn't know what's going on."

Inside the apartment, police found the bodies of Himmelman and Oneschuk. Both had been shot in the head and upper body, police said.

Arthurs told officers the four men all had been friends who shared common neo-Nazi beliefs until Arthurs converted, police said.

He told police the "shooting stemmed from Himmelman and Oneschuk disrespecting Arthurs' Muslim faith," the police report states.

Arthurs also said he had "been privy to Russell participating in online neo-Nazi Internet chat rooms where he threatened to kill people and bomb infrastructure," the FBI reported.

Arthurs faces two counts of first-degree murder, two counts of aggravated assault and three counts of armed kidnapping.

Explosives, weapons, photo of McVeigh

The FBI said agents found explosive materials in the apartment, which was leased by Russell. He was charged by the FBI with possession of an unregistered destructive device and unlawful storage of explosive material, according to the criminal complaint filed in U.S. District Court.

Inside Russell's bedroom, the FBI found Nazi propaganda, a framed photo of Oklahoma City bomber Timothy McVeigh, guns, ammunition and two radiation sources, the FBI said.

Russell admitted being a national socialist, making the explosive material, and being a member of a group called the "Atom Waffen," or "atomic weapon" in German, the FBI said.