Is this the most damning attack from Republican presidential candidate Donald Trump against rival Hillary Clinton?

Trump is suggesting that Clinton’s emails may be directly responsible for the death of an Iranian nuclear scientist who was executed for spying for the United States.

“Many people are saying that the Iranians killed the scientist who helped the U.S. because of Hillary Clinton’s hacked emails,” Trump said.

Trump isn’t the first to suggest there could be a link between Clnton’s emails on her private server and the execution of Shahram Amiri.

Some of the Clintons harshest critics agree, saying Amiri is just the latest victim of the Clinton family’s political ambitions.

Arkansas Republican Sen. Tom Cotton said on CBS’s “Face the Nation” Sunday that there “were on Hillary Clinton’s private server, there were conversations among her senior advisers about this gentleman.”

“That goes to show just how reckless and careless her decision was to put that kind of highly classified information on a private server,” he said.

Amiri, an Iranian scientist, defected to the U.S. at the height of Western efforts to thwart Iran’s nuclear program. When he returned in 2010, he was given a hero’s welcome and greeted with flowers by government leaders. Then he mysteriously disappeared.

Amiri’s case indirectly found its way into the spotlight last year with the release of State Department emails sent and received by Clinton.

One email forwarded to Clinton by senior adviser Jake Sullivan on July 5, 2010 — just 10 days before Amiri returned to Tehran — appears to reference the scientist.

“We have a diplomatic, ‘psychological’ issue, not a legal one. Our friend has to be given a way out,” the email by Richard Morningstar, a former State Department special envoy for Eurasian energy, read. “Our person won’t be able to do anything anyway. If he has to leave, so be it.”

Another email, sent by Sullivan on July 12, 2010, appears to obliquely refer to the scientist just hours before his appearance at the Iranian-interests section at the Pakistani Embassy in Washington became widely known.

“The gentleman … has apparently gone to his country’s interests section because he is unhappy with how much time it has taken to facilitate his departure,” Sullivan wrote.

Clinton’s decision to store her emails on a private server in her New York home sparked an FBI investigation and has become a dominant issue in the presidential campaign.

The Associated Press contributed to this article