Linda Damm's 15-year-old daughter Tess and her boyfriend Bryan Grove appeared in court for the hearing where a Boulder County forensic pathologist took the stand.
John Meyer discussed the autopsy performed on the 52-year-old woman who was found Feb. 28 in the trunk of her car in her garage in Lafayette.
Meyer told the court he found 18 stab wounds on her neck and ruled that the cause of death.
Detective Scott Robinson testified that Bryan Grove stated he first tried to strangle Damm after an argument they had. She passed out, and according to the detective, Grove stabbed her with one knife and then another one.
Robinson said Grove also bought a saw with Damm's debit card and tried to dismember her, but that didn't work.
Defense for Grove asked if police had physical evidence that linked the 17-year-old to the murder.
An investigator said items collected at the scene have not yet been tested.
The couple's teenage friend is expected to testify against them.
Damm's family was in court on Monday. An uncle says all this is tough.
"I can't really describe the conflict and the pain, the loss of my sister and the loss of my niece at the same time," said John Schueller. "We don't really know Tess. When she came to our house, she was always just a young little girl with her mom on holidays. We don't know this angry young woman."
At one point during the proceedings, both Grove and Damm smiled at their supporters in the court room.
Tess Damm was originally charged with conspiracy to commit first-degree murder after the body of her mother was found, but prosecutors have added a first-degree murder charge against her.
Grove, 17, faces charges of first-degree murder, conspiracy to commit first-degree murder and tampering with physical evidence.
Both Damm and Grove are being charged as adults. Conviction of first-degree murder carries a sentence of up to life in prison. The sentence for conspiracy to commit first-degree murder is 16 to 48 years in prison.
(Copyright KUSA*TV, All Rights Reserved. The Associated Press contributed to this report.)