Bennet Omalu, Ira R. Casson

Dr. Bennet Omalu, left, Co-Director, Brain Injury Research Institute, West Virginia University talks with Dr. Ira R. Casson, Neurologist and former co-chairman, NFL Mild Traumatic Brain Injury Committee, before a House Judiciary Committee hearing entitled "Legal Issues Relating to Football Head Injuries, Part II" in Detroit, Monday, Jan. 4, 2010. The House Judiciary Committee heard from retired players at the hearing today on head injuries in football, following up an Oct. 28 hearing in Washington where lawmakers questioned NFL football commissioner Roger Goodell about the league's approach to concussions. (AP Photo/Paul Sancya)

(Paul Sancya)

Bennet Omalu, a forensic pathologist who discovered chronic traumatic encephalopathy in the brains of deceased NFL players, has called on Hillary Clinton's Democratic presidential campaign to check the former first lady for signs of being poisoned.

Following Clinton's near-collapse in New York City on Sunday -- something which her campaign attributed to pneumonia -- Omalu took to Twitter to offer his own medical advice to the White House hopeful, the Washington Post reported.

The doctor, whose story was portrayed in the movie "Concussion," urged Clinton's team to perform toxicologic analysis of the former secretary of state's blood.

"It is possible she is being poisoned," he tweeted.

I must advice the Clinton campaign to perform toxicologic analysis of Ms. Clinton's blood. It is possible she is being poisoned. — Bennet Omalu (@bennetomalu9168) September 12, 2016

Although Omalu did not explicitly accuse anyone of being behind such an alleged poisoning, he later tweeted that he does not trust Republican presidential nominee Donald Trump and Russian President Vladimir Putin, who have exchanged praise with each other in recent months, according to the newspaper.

I do not trust Mr. Putin and Mr. Trump. With those two all things are possible. — Bennet Omalu (@bennetomalu9168) September 12, 2016

A British inquiry implicated Putin earlier this year in the 2006 poisoning death of Alexander Litvinenko, a former KGB operative, in London, the Post previously reported.

Top U.S. national security officials, meanwhile, have accused Russian intelligence agencies of hacking the Democratic National Committee.

Clinton, whose walking was aided by staff members, stumbled as she left the 9/11 memorial ceremony, sparking new questions about her health and fitness to serve as president.

Her doctor attributed the incident to the former secretary of state becoming "overheated and dehydrated," the Associated Press reported. Clinton's campaign later released a statement from her doctor saying she was diagnosed with pneumonia on Friday.