A woman was probably still alive when a stranger started removing her unborn baby, a trial in Missouri has heard.
Mrs Stinnett thought her visitor was coming to buy a puppy
Bobbi Jo Stinnett, who was eight months pregnant, fought for her life, and that of her child, after being attacked by Lisa Montgomery, the trial heard.
Mrs Montgomery denies strangling Mrs Stinnett and kidnapping her daughter, Victoria Jo, in December 2004.
Prosecutors said a doctor would testify that Stinnett was probably alive "when the baby was being cut from her womb".
Prosecutor Matt Whitworth said searches of Mrs Montgomery's computer showed she had researched how to perform caesarean sections and he added: "This defendant spent a great deal of time planning this crime."
Mrs Montgomery, 39, allegedly used a kitchen knife to cut the baby from the womb and used information on home births which she had downloaded from the internet. She has pleaded not guilty.
Mrs Stinnett's body was discovered by her mother, Becky Harper, who told the court: "There was blood everywhere."
Lisa Montgomery's lawyers say she was mentally ill
The little girl survived and was traced to Mrs Montgomery's home in Melvern, Kansas. She was later reunited with her father and is now almost three years old.
The court heard how police tracked the mother-of-four down through e-mails she had sent the victim in which she purported to be interested in buying a dog from her.
The trial is due to last three weeks and prosecutors have said they will seek the death penalty if Mrs Montgomery is convicted.
Mrs Montgomery's lawyer, Fred Duchardt, said the defence would not deny Mrs Montgomery's involvement in Mrs Stinnett's death but would seek to prove she was suffering from mental illness.
He said she had suffered for years after being raped by her stepfather as a child.
Mr Duchardt said Mrs Montgomery had been suffering from a condition called pseudocyesis, which caused her to falsely believe she was pregnant.
He said she had been pushed over the edge by an impending custody battle with her former husband.
The first witness to be called was Nodaway County Sheriff Ben Espey, who was the first law enforcement officer to arrive at the Stinnetts' home in Skidmore, Missouri, after a 911 call by Mrs Harper.
"You could see swirls in the floor in the blood, showing there was a struggle," said Mr Espey.