May 3, 2013 -- The death of a Pennsylvania doctor who had "toxic levels of cyanide" in her system is being investigated as a possible homicide and a possible suicide, authorities said today, before later launching a search of her home.
This evening, investigators with the Pittsburgh police and FBI descended on Autumn Marie Klein's residence, where they were in the process of conducting an extensive search of the home and backyard. Two Mobile Crime Scene Units were stationed in plain view in front of the house.
Investigators declined to discuss precisely what they were doing or looking for but they confirmed to ABC News that they were in the process of an "official search" of the home. Two investigators, wearing blue lab gloves, were seen carrying in large garbage bags.
Klein, 41, collapsed at her home in Pittsburgh's Oakland neighborhood and later died on April 20 at UPMC Presbyterian Hospital, where she was chief of the division of women's neurology and an assistant professor of neurology, obstetrics and gynecology.
Officials were tight-lipped about the investigation. When asked if the case was being looked at as a suicide or a homicide, Mike Manko of the Allegheny County District Attorney's Office told ABCNews.com., "Both are being looked at."
"There have been some warrants executed," Manko said. The warrants were for "PITT and/or UPMC," he said.
Klein worked at UPMC Presbyterian Hospital. Her husband, Dr. Robert Ferrante, 64, is a professor of neurological surgery at University of Pittsburgh. The couple had a 6-year-old daughter named Cianna.
"We are not naming anyone as a person of interest," Lt. Kevin Kraus of the Pittsburgh Police Department told ABCNews.com. "It's a complex investigation and we're working closely with the medical examiner and the district attorney's office as we proceed."
A private investigation has also been launched.
"I have been privately retained, but I'm not able to give you any more information. But I have been privately consulted in this matter," Cyril Wecht told ABCNews.com when asked if he was retained by Dr. Robert Ferrante or his attorney.
Wecht is a prominent forensic pathologist best known for his controversial role in the John F. Kennedy assassination investigation.
Klein's mother, Cook Klein, 79, lives in Towson, Md., and says she cannot imagine anyone wanting to hurt her daughter "because of the type of person she was."
"She was just a wonderful human being and a fantastic mother," an emotional Cook Klein said. "She was a person that cared for everybody. She was an absolutely wonderful mom. There was nothing about her that anybody would not like."
Cook Klein said her humble daughter had been selected by the American Academy of Neurology as one of the 10 most promising neurologists in the country and that three people at the funeral home told Cook Klein that they were working on publications with Klein. The three had traveled from Ohio, Florida and Canada to be at the funeral.
When Cook Klein got word of her daughter's death she and her husband were preparing to travel to Pennsylvania to babysit the daughter while the parents went out of town for a medical event. Cook Klein was packing her suitcase late the night before she was set to leave when she said Ferrante called her.
"Bob was saying something had happened to Autumn and he was there in the house by himself with Cianna," Cook Klein said. "He had called 911 and they had taken Autumn to the emergency room."
Cook Klein said she was initially told her daughter may have suffered a stroke.
When she heard about the cyanide, her first concern was her granddaughter and who would pick her up from school if police needed to speak to her father. Cook Klein said police told her that Cianna was with her father.
She said her young granddaughter "just knows her mommy isn't home."
Neither Ferrante nor his attorney responded to requests for comment.