It sounds like an unlikely leap of faith: a neo-Nazi converting to Islam.

But according to records and at least one friend who knew him, that's what 18-year-old Devon Arthurs did about a year before he allegedly killed two roommates in a Tampa Palms apartment on Friday. According to police report, Arthurs said he previously had neo-Nazi beliefs in common with Jeremy Himmelman and Andrew Oneschuk, but shot them Friday because they disrespected his new faith. Arthurs also said he was angry about anti-Muslim sentiment and the United States bombing Muslim countries.

There are some documented cases of white supremacists and other right-wing extremists shifting to Islamic extremism, according to Mark Pitcavage, a senior research fellow at the Anti-Defamation League's Center on Extremism.

In several cases, the converts were "young people with seemingly fluid beliefs, and who may have had more of a desire either to belong to something or cause chaos rather than pure dedication to a particular cause," Pitcavage said in an email to the Tampa Bay Times.

PREVIOUS COVERAGE: Neo-Nazi in Florida National Guard arrested after explosives found at Tampa Palms murder scene

The level of chaos that Arthurs was willing to create came into question Tuesday, when the Times obtained court filings that revealed he told police he had yet another motive for killing Himmelman and Oneschuk: to stop them and a third roommate, Brandon Russell, from carrying out an act of domestic terrorism. Investigators found explosives and bomb making supplies in the apartment's garage and charged Russell in connection to the materials.

According to a report by the Southern Poverty Law Center, the federal investigation and prosecution of Joseph Jefferey Brice highlights the antigovernment, anti-Semitic links shared between Islamic jihadists and white supremacists.

Brice, of Clarkston, Wash., idolized Oklahoma City bomber Timothy McVeigh and nearly died exploding a test bomb before becoming interested in radical jihadists. But the former "self-declared, conservative, right-wing Christian," appeared to undergo a rapid radicalization to Islam when an acetone peroxide ammonium nitrate bomb he built prematurely exploded near his rural home in eastern Washington in April 2010.

Federal prosecutors concluded the homemade bomb that left Brice unconscious for 12 days "was the result of years of internet research, experimentation with dangerous chemical mixtures, and involving others in both the manufacturing process and the detonation of pipe bombs and chemical IEDs."

Later, recovering from severe injuries, Brice became interested in Islamic extremists and attempted to communicate with members of that movement via social media, ultimately providing them with bomb-making formulas. Instead of labeling Brice as an Islamic jihadist convert or a white supremacist, Brice appeared more interested in a religion of "violence and chaos," according to federal investigators.

He was sentenced in 2012 to 12.5 years in federal prison after pleading guilty in federal court to manufacturing an illegal explosive device and attempting to provide material support to terrorists.

In February, German police arrested a 26-year-old man on suspicion of plotting an Islamist-inspired attack. The man, identified only as "Sascha L.," is accused of plotting to lure police officers and soldiers into a trap, according to published reports. When authorities searched his apartment in Northeim they found chemicals and electronics that could be used to make explosives, according to Der Spiegel.

Investigators also found evidence that he'd been a neo-Nazi as recently as 2013, when a man thought to be Sascha uploaded video warning of the threat posed by Muslims, whom he accused of trying to impose Islamic law on the country, as well as left-wing activists and anti-fascists.

A year later, investigators believe, he converted to Islam. On Facebook, Sascha liked a regional Islamist extremist group's page and changed his profile to include the slogan "Don't push! I have a bomb in my backpack." Sascha also faced a court case over spreading the prohibited symbols of the Islamic State militant group on the Internet.

Seamus Hughes, deputy director of the Program on Extremism at George Washington University, told the Washington Post after Sascha's arrest that extremists sometimes make unlikely shifts because of common enemies.

"There are some overlaps in terms of groups both sides hate so [there is] an easier transition from one extreme to the other," Hughes said.

David Wulstan Myatt, a neo-Nazi who served as the first leader of the British Nationalist Socialist Movement and wrote a pamphlet called "A Practical Guide to Aryan Revolution," converted to Islam in 1998. Myatt told author George Michael that he was impressed by the militancy of Islamist groups and believed that he shared common enemies with Islam, namely "the capitalist-consumer West and international finance."

A dozen years later, Myatt announced that he was rejecting Islam in favor of his own worldview that he called the Numinous Way, which he described as an apolitical faith based on empathy.

Contact Tony Marrero at tmarrero@tampabay.com or (813) 226-3374. Follow @tmarrerotimes.