Robert Ferrante’s voice was pleading, panic-stricken.

For nearly 12 minutes, the now-66-year-old neurological researcher for the University of Pittsburgh begged a 911 dispatcher to get help for his wife at their Lytton Avenue home in Oakland.

“Hello, hello. Please, please, please, please. I think my wife is having a stroke,” he said.

Mr. Ferrante told Jonathan Hamburger, the 911 call-taker, that the couple’s 6-year-old daughter was asleep upstairs, and that his wife, Autumn Klein, had just gotten home from work and was on the kitchen floor. He called 911 at 11:52 p.m. -- telling the dispatcher his wife had been in that state for no more than 10 minutes.

The prosecution played a recording of the call Thursday afternoon during the first day of Mr. Ferrante’s trial on one count of criminal homicide. Police say he ordered cyanide from his lab and poisoned his wife of nearly 12 years with it.

“All along, the evidence will show you, this defendant thinks he’s smarter than everyone else,” said assistant district attorney Lisa Pellegrini. Mr. Ferrante, she continued, was “one blood test, and one phone call ... from getting away with the perfect murder.”

The defense told the jury, though, that the symptoms Dr. Klein exhibited when paramedics first arrived on the scene were inconsistent with cyanide poisoning.

Among them were that she was breathing normally, had a strong pulse, low blood pressure and her pupils were normal.

“Myself and Dr. Ferrante do not accept — and will never accept — that Autumn Klein died from orally ingesting hydrogen cyanide,” said defense attorney William Difenderfer in his opening statement. “And they can’t prove it.”

Ms. Pellegrini began her case with the 911 recording.

The call alternates between Mr. Ferrante’s apparent desperation and horrific groaning noises from Dr. Klein in the background.

“She’s just staring and can’t answer,” he said. "Yes, yes, the whole face is flaccid except for these big white eyes."

Following Mr. Hamburger’s instructions, Mr. Ferrante asked Dr. Klein to raise her arms above her head.

“Please, please, please, please,” he pleaded. “She's not saying a word. Please, sweetheart! No!.”

Throughout the call, Mr. Ferrante’s demeanor switched from that of a person educated in medicine -- “she has this sort of athetoid,” “She’s audibilizing.” -- to a layman, “Now she’s grunting. Her arms are just stiff.”

When paramedics finally arrived at the couple’s home, they took Klein to UPMC Presbyterian -- even though Mr. Ferrante asked the 911 dispatcher to have his wife taken to UPMC Shadyside, Ms. Pellegrini told the jury.

Dr. Andrew Farkas, who was a resident at Presby and the first doctor to treat Dr. Klein, was the fourth and final witness to testify Thursday.

Soon after her arrival, Dr. Klein was put on a ventilator, and later went into cardiac arrest for 25 minutes. When Mr. Ferrante got to the hospital, Dr. Farkas said, he pulled back the curtain, and “He took a long look at her, kind of sizing things up, and then screamed ’No!’ kind of loudly and dramatically.”

During Dr. Klein’s treatment, Dr. Farkas put a central IV line in to be able to better give her medications. When he put it in her internal jugular vein, “I noticed that the blood that came out was bright red.”

That clue, the prosecution said, ultimately led doctors to test Dr. Klein’s cyanide levels. But after the blood was drawn, it was shipped to a lab in Virginia, and the results did not return until after she died on April 20.

When Dr. Farkas saw what was a fatal level, he called the medical examiner’s office.

“Boom,” Ms. Pellegrini said. “They call to get Autumn’s body back, but she’s already been cremated.”

Mr. Ferrante had her body cremated two days after the autopsy.

In her opening statement, Ms. Pellegrini called Dr. Klein a “shining star.”

Still, the prosecutor continued, Dr. Klein was unhappy in her marriage to the much older man -- Dr. Klein was 41 when she died -- but also wanted another child.

Ms. Pellegrini told the jury that in January 2013, Mr. Ferrante became jealous of a man with whom Dr. Klein had previously worked in Boston, and with whom she remained friends.

Around that same time, Mr. Ferrante started doing Google searches about cyanide poisoning, Ms. Pellegrini said. He searched the background of Dr. Klein’s friend, Tom McElrath. And when his wife was at a conference in San Francisco with Dr. McElrath, Mr. Ferrante Googled, “suicide on Golden Gate Bridge.”

After Dr. Klein died, Ms. Pellegrini said, Mr. Ferrante did additional searches, “’detecting cyanide poison,’” and “ ’How would a coroner detect if someone died from cyanide.’

“That was before he was supposed to know that’s how she died,” Ms. Pellegrini said.

But Mr. Difenderfer, during his 45-minute opening, told the jury that his client had nothing to do with Dr. Klein’s collapse and death.

But more than that, he said that the test results from the original blood sample taken at the hospital were changed. The original reading from Quest Diagnostics, Mr. Difenderfer said, was 3.4 milligrams of cyanide per liter, but later the report’s calculations were changed to 2.2.

Another test, run after Dr. Klein’s death by another lab, showed she did not have fatal levels of cyanide in her blood, he said.

“Our experts can’t say it’s cyanide poisoning — plain and simple,” he said.

(Click here to read the transcript of the call.)

Correction (posted Oct. 24, 2014): An earlier version of this story had an incorrect first name for Mr. Hamburger.

First Published: October 23, 2014, 3:49 p.m.
Updated: October 24, 2014, 3:27 a.m.