PORTLAND, Ore. (AP) — A woman whose unborn son was cut from her body put up a violent, bloody struggle for survival with her killer, according to court documents.

Heather Snively’s infant did not survive.

She had bite marks on the back of one elbow, and the woman accused of killing her had a five-inch scratch on the left side of her neck and visible injuries on her arms, Washington County Sheriff’s Detective Murray Rau wrote in a search warrant affidavit released Monday.

“The scene of this crime was very bloody, and, based on my own observations of the physical evidence, was the scene of a violent struggle involving the suspect and the victim,” Rau wrote.

Korena Roberts, 27, has pleaded not guilty to aggravated murder and other charges in the death of 21-year-old Snively, whose body was found June 5 in the crawl space at the house Roberts and her boyfriend rented west of Portland.

Investigators believe Snively, who had recently moved to the state from Maryland, met Roberts through an online classified service, where both were looking for baby clothes.

The documents released by a Washington County judge include an account from Yan Shubin, Roberts’ boyfriend of the past five years. No charges were filed against him.

Shubin said Roberts told him she was pregnant with twins. She gained weight, took prenatal vitamins and attended midwife classes at a community college. Roberts also reported making trips to a doctor, but when the pair went for an ultrasound appointment it turned out nothing had been scheduled.

When Shubin returned home from work for lunch on June 5, Roberts made him a sandwich and everything seemed normal.

At 2:30 p.m., he received an urgent call.

According to Shubin, Roberts said “I need you” and sounded like she was in pain.

When he arrived home, he saw blood on the floor and found Roberts sitting in the bathtub with a lifeless infant.

Paramedics took Roberts and the child to a hospital, where doctors quickly determined the baby was dead and that Roberts had not just given birth.

According to the court documents, Roberts claimed the baby had a twin, and Shubin told authorities there was possibly another baby at the house.

While officers searched the house in vain for another baby, Shubin called them from the hospital.

“According to Yan, Korena told him that she did a horrible thing,” the documents state.

Shubin told detectives about the crawl space where a sergeant found Snively’s body.

The sergeant “told me that the body was very ashen, and he could see that the abdomen was sliced open,” Rau wrote.

Prosecutors have not said how Snively was killed, other than autopsy results which showed blunt force trauma. The type of tool used to cut Snively’s abdomen also was not disclosed. Shubin told investigators a pack of razor blades he bought went missing two days before Snively’s death, the documents state.

Authorities have not said why they believe Roberts would fake a pregnancy and try to steal a baby.