Washington, April 26 -- Speculation about links among a handful U.S. scientists who have died or disappeared in recent years was largely confined to niche online communities less than two months ago. As of Friday, the number had grown to at least 12 and was at the epicenter of U.S. government, with both the FBI and Congress investigating possible connections. At a press gathering April 16, President Donald Trump was asked about "10 missing scientists with access to classified stuff, nuclear material, aerospace, they've all gone missing or turned up dead in the last couple of months" and whether he thought there were ties among them. "Well, I hope it's random, but we're going to know in the next week and a half, " Trump said. Those speculating about the cases suggest that the individuals were targeted, perhaps by global U.S. adversaries, because of the sensitive nature of their work related to topics such as astrophysics, nuclear weapons and pharmaceuticals. But so far no evidence has been found that definitively links them or establishes coordinated foul play. Jen Golbeck, a professor at the University of Maryland who studies conspiracy theories, said the idea of a sinister connection between tragedies involving scientists is a common trope within conspiracy theory communities. "There are a lot of people who work for national labs and universities and government research centers and some of them will go missing or commit suicide or die," she said. "Any year you could take a bunch of those and name them as something sinister if you wanted to." The deaths and disappearances in question garnered suspicion from online sleuths as they occurred, but it was the disappearance of 68-year-old William "Neil" McCasland, a retired Air Force general, on Feb. 27 that fueled a wider belief that there could be a nefarious connection between these incidents, spurred in part by his high-ranking military work and connection to the UFO community. Around this time people began pointing to other examples of scientists who had died or gone missing, ultimately going as far back as June 2022. The Daily Mail published an article on March 22 naming five individuals and reporting that "a chilling pattern has emerged after a string of US scientists died or went missing in recent months." On April 15, a question about the missing or dead individuals came up at a White House press briefing and by the next day Trump said he had met with advisers and the issue was being investigated. FBI Director Kash Patel reiterated the importance of looking for connections in these cases Sunday on Fox News. The House Committee on Oversight and Government Reform is conducting its own investigation. "That's pretty typical for how a lot of this stuff works, is that there are these fringe online spaces, they start it, it spreads, it gets picked up by ... the more conspiratorial-minded politicians who do have platforms and makes its way onto more mainstream social media and then grabs that attention," said Golbeck. Callie Kalny, co-director of the Center of Media Psychology and Social Influence at Northwestern University, agreed that these conspiracy theories are following a familiar pattern of starting in more niche venues before finding their way into the national conversation....