The accused Nashville suicide bomber was reportedly paranoid about 5G technology. Here's what we know about the false 5G conspiracy that went viral this year.

• On Christmas morning, a suicide bombing shook Nashville. The explosion injured three and damaged 41 buildings, Business Insider previously reported.
• The FBI said Anthony Quinn Warner, who was in the van that exploded, was responsible for the bombing. Besides Warner, there were no casualties.
• While the investigation is ongoing, the local NBC affiliate reported that investigators were looking at Warner's obsession with 5G conspiracy theories, which may have caused him to target the AT&T building in Nashville.
• Here's what we know about the false 5G conspiracy theories.

Anthony Quinn Warner, who the FBI says was responsible for the suicide bombing that hit Nashville on Christmas Day, may have been motivated by 5G conspiracy theories to carry out the attack, as local NBC affiliate, WSMV, reported.

Although the federal investigation is ongoing, a source told the Daily Mail that investigators theorize Warner believed that 5G was responsible for his father's death, and had purposefully targeted an AT&T building in Nashville as a means of striking against telecommunications giants.

Since the outbreak of the COVID-19 pandemic, the false theory that 5G, the next generation of cellular infrastructure, is responsible for ills from cancer to COVID-19 itself, has become increasingly popular. Here's a simple explanation of the false theory, and how it has risen to influence.

Read more: Google's misinformation chief talks fact-checking the pandemic: 'I've never seen anything like this'

What does the theory claim?

There's a whole constellation of theories about 5G, but most boil down to the idea that 5G produces radiation that is harmful to human health. Some unsupported theories say that 5G damages trees, others say that it weakens the immune system and causes cancer, and still others say that Bill Gates is using 5G to brainwash Americans.

Since the outbreak of the COVID-19 pandemic, new claims about 5G have emerged. Some social media posts falsely claimed that COVID-19 is a cover-up for illnesses caused by 5G, others purported that 5G had accelerated the spread of COVID-19.

How did it start?

Suspicions about telecommunications and health concerns have a long history. People protested when 3G was rolled out in the 90s, and before that, they protested cell phones themselves, Full Fact, a UK-based anti-misinformation nonprofit, reported.

Much of the misinformation about 5G can be traced to the work of Dr. Bill Curry, who shared a chart claiming that radio waves become more dangerous to brain matter at higher frequencies back in 2000, the New York Times reported. But, his claims of risk were overblown, scientists said, since it didn't account for the fact that the skin protects the brain from high-frequency radio waves.

How did the latest 5G theory spread?

The misinformation about high-frequency waves was distributed by the state-run television network Russian Today, according to a 2019 New York Times report. RT - which was also linked to the Russian campaign to influence the 2016 election - broadcasted, without evidence, that 5G can cause health issues like autism and cancer. Once the coronavirus pandemic hit, conspiracy theorists linked the two, even leading to some people in the UK setting telephone poles on fire.

The misinformation circulated on social media, too. Facebook posts listing "5G illness" symptoms and 5G conspiracy groups proliferated online. Public figures like newscasters and celebrities have also spread the unsupported theory, as the New Statesman reported.

Read more: COVID-19 has triggered a new wave of conspiracy theories among those who fear a 'cashless society'

Does 5G pose a health risk?

Experts say no. 5G radiowaves are "non-ionizing radiation," which means that they don't have the power to damage the DNA inside of cells. And despite claims that 5G is a higher frequency radio waves, and therefore is more dangerous than 3G and 4G networks, the opposite is true, scientists say.

"It's a little ironic that there's all this worry about 5G," Chris Collins, a professor at the New York University School of Medicine's radiology department, told CNN Business. "It really doesn't get past the skin."