Investigators said it would take a few weeks for test results to confirm cyanide poisoning but the initial investigation showed indications of toxic levels of cyanide in the bloodstream of Dr. Autumn Klein, who died last month, WPXI-TV, Pittsburgh, said.
"I do not believe this could have been an accident," said Rick Lorah, forensic supervisor for the medical examiner. "The death of this 41-year old physician is highly suspicious."
Pittsburgh police, the Allegheny County coroner and the FBI are investigating.
Detectives this week executed a search warrant at a laboratory at the University of Pittsburgh Medical Center where Klein's husband, Robert Ferrante works, CNN said.
Ferrante is co-director of a research center looking into Lou Gehrig's disease.
Klein was involved in neurological research at the university and worked in a lab where cyanide was present. However, investigators said accidental cyanide poisoning is rare.