President Donald Trump said the connection between several missing or dead scientists and workers with ties to advanced research is “minimal.” The cases of these scientists have led to claims that there is a link.

Reports and online rumors for weeks had made people wonder if there was a link between a string of deaths and disappearances that had happened over a few years. The incidents got the attention of the public, lawmakers, and government agencies.

Trump drew even more attention to the events earlier this month when he called them “pretty serious stuff” and said he hoped it was just an accident, but “some of them were very important people.”

A day earlier, White House Press Secretary Karoline Leavitt said the situations would be looked into by the government.

Trump’s new comments seem to calm down recent rumors, which have grown in recent weeks, even though officials haven’t confirmed a direct link between the cases. The FBI and NASA have both started investigations.

“There are thousands or even hundreds of thousands of scientists working for us, so 10 is a lot, but it’s still a very small number compared to that. Some of them that we looked at are very sad cases, in some cases, some were sick, some left this earth self-inflicted. Some had other things,” Trump told reporters.

He added, “So far, we’re finding that there’s not much of a connection. We’ll let you know.”

A U.S. congressman said on Thursday that he would investigate the mystery behind the deaths or disappearances of 13 scientists in the previous few months. This came as President Donald Trump offered an update on the federal government’s probe.

“The count is up to 13. Thirteen American scientists tied to nuclear and space research, missing or dead,” Rep. Eric Burlison, R-Mo., said on X. “Every adversary on the planet celebrates each one we lose. We are weaker as a nation today because of these losses, and I’m working to get answers.”

“I asked the FBI directly if they had opened an investigation into Matthew Sullivan’s suspicious death,” he said in a later post. “They would not confirm or deny. I’ve been pushing on this for almost a year. The American people deserve straight answers from their FBI. Period.”

The New York Post says that Sullivan, who was 39 years old, died of an accidental drug overdose in his home in Falls Church, Virginia, on May 12, 2024. This was just after he agreed to testify before Congress about government UFO activities.

The Post said that Sullivan was a U.S. Air Force intelligence officer who won a Bronze Star during Operation Enduring Freedom. Thereafter, he worked for the National Air and Space Intelligence Center, the National Security Agency (NSA), and the Air Force Intelligence Agency.

The theories about the missing and deceased scientists started after retired Air Force Maj. Gen. William Neil McCasland went missing earlier this year. He used to be responsible for the Air Force Research Laboratory and had ties to the Los Alamos National Laboratory, where top-secret nuclear research is done.

Since 2022, at least 13 people have died or gone missing, including Sullivan. Most of them were working in nuclear science or space exploration, and several of them did so under strange circumstances.

Monica Reza, 60; Melissa Casias, 53; Anthony Chavez, 79; and Steven Garcia, 48, all went missing between 2023 and 2026, and each of their disappearances was considered suspicious.

All of these people died between 2022 and 2026: Michael David Hicks, 59; Frank Maiwald, 61; Nuno Loureiro, 47; Jason Thomas, 45; Amy Eskridge, 34; Carl Grillmair, 47; and Joshua LeBlanc, 29.

Reports of multiple scientists connected to U.S. aerospace and defense programs who have died or gone missing since 2022 have drawn new attention following action by congressional investigators, though authorities have not confirmed any link between the cases.

The House Oversight Committee on Monday requested information from several federal agencies regarding the deaths and disappearances of at least 11 researchers with ties to organizations such as NASA and private companies, including SpaceX and Blue Origin.

Committee Chairman James Comer and Rep. Eric Burlison sent letters to Kash Patel, Energy Secretary Chris Wright, Defense Secretary Pete Hegseth, and NASA Administrator Jared Isaacman, requesting staff-level briefings by April 27, Fortune magazine reported.