A researcher whose wife died of cyanide poisoning in April is expected to be arrested in Florida and then returned to Pittsburgh to face a charge of criminal homicide.
The arrest, to be made by the Pittsburgh police, is "imminent," sources said.
William Difenderfer, who represents Robert J. Ferrante, a professor of neurological surgery, said he was disappointed with the development.
"He's adamant he had nothing to do with her death and plans to fully defend himself," Mr. Difenderfer said.
Autumn Klein, the chief of the division of women's neurology at UPMC, collapsed at her Oakland home around 11:30 p.m. on April 17 and was rushed to UPMC Presbyterian.
Records reviewed by the Pittsburgh Post-Gazette showed that Mr. Ferrante called 911 at 11:52 p.m. that day and told dispatchers he thought his wife might have had a stroke because she had been "just staring off into space" for about 10 minutes and then started groaning.
Over the next few days, he explained to his 6-year-old daughter, Cianna, how her mother's brain function had flatlined and asked other medical professionals for their opinions about what they thought might be the cause, Dr. Klein's mother, Lois Klein, told the Post-Gazette in a previous interview.
Dr. Klein was pronounced dead on April 20.
Allegheny County Medical Examiner Karl Williams has said that toxic levels of cyanide were found in Dr. Klein's body, and the death was initially investigated as either suicide or homicide.
Over the ensuing months, dozens of search warrants have been obtained, and the investigation, being handled by prosecutors from the Allegheny County District Attorney's homicide and white-collar offices, has included assistance from the FBI.
Included within the subpoenas and search warrants were one for the couple's home and one for the University of Pittsburgh, pertaining to cyanide.
The highly lethal chemical interferes with the ability to breathe and can render a person unconscious quickly.
Although it is hard to obtain, it is used in university and pharmaceutical labs.
Mr. Ferrante, a leading researcher in ALS and Huntington's Disease, spent more than 20 years in Boston, working at Harvard Medical School, Massachusetts General Hospital and Boston University, before moving to Pittsburgh in 2011 when his wife was offered the position with UPMC.
In Boston, she served as chief resident in neurology at Brigham and Women's Hospital in Boston and had a faculty appointment at Harvard Medical School.
Her specialty included treating pregnant women with neurological diseases. She also was an assistant professor of neurology and obstetrics and gynecology at UPMC.
Pittsburgh homicide detectives traveled to Boston in May as part of their investigation into Dr. Klein's death. Representatives from Boston facilities where the couple worked declined to comment on whether they had contact with Pittsburgh police.
Dr. Karen Roos, who edited several articles Dr. Klein wrote for Seminars in Neurology and stayed in regular contact with her until her death, said the couple met when Dr. Klein was doing her residency.
She said Dr. Klein wanted to have another child, possibly within a year. Dr. Klein occasionally mentioned her husband but spoke primarily about her daughter, Dr. Roos said.
"She did not run into cyanide in the context of her research," Dr. Roos said. "I am absolutely a million times positive of this. There's probably no neurologists using cyanide in the context of her research."
News of a possible arrest comforted Dr. Roos, who said she was confident her friend did not commit suicide.
"She would have never taken her own life," Dr. Roos said. "It just never would have happened."
Correction, posted July 25, 2013: An earlier version of this story mischaracterized Dr. Karen Roos' understanding of Dr. Autumn Klein's attempt to have another child. Dr. Roos said she did not know whether Dr. Klein was using fertility drugs.
Liz Navratil: email@example.com, 412-263-1438 or on Twitter @LizNavratil. Paula Reed Ward: firstname.lastname@example.org, 412-263-2620 or on Twitter @PaulaReedWard. First Published July 25, 2013 4:00 AM