(CNN) -- A woman whose body was found in the crawl space of an Oregon home -- the mother of a newborn who also died -- died from "homicidal violence," the state's deputy medical examiner said Monday.
Police released a photo of Korena Roberts, who is charged with murder.
An autopsy showed causes of 21-year-old Heather Snively's death included blunt-force trauma and "sharp-force injuries," Dr. Christopher Young said. Sharp-force injuries mean cut or stab wounds. Young said additional information will not be released until test results are received.
Korena Roberts, 28, is charged with murder in Snively's death. She was scheduled to appear in court Monday afternoon.
Medics received a call Friday from Roberts' Washington County, Oregon, home of a newborn in distress, authorities said. When they arrived, they found Roberts' boyfriend trying to revive the baby boy. Roberts told deputies the baby was hers, according to the county sheriff's office.
Roberts and the baby were taken to a hospital after medics noticed a lot of blood at the home, officials said.
"Doctors at the hospital could not revive the baby," said sheriff's Sgt. David Thompson. "They also discovered that Ms. Roberts had not delivered the baby at any time in the recent past."
Deputies returned to the home and found Snively's body in a crawl space beneath the kitchen. Police said she had been pregnant; authorities determined she was the baby's mother.
"At this time, it has not been determined if [Snively] died because of head wounds she received or as a result of cutting injuries she received to her abdomen," said a Monday statement from the Washington County, Oregon, Sheriff's Office. "The autopsy determined that Ms. Snively's son was removed from her womb after she had been cut open."
Additional testing is needed to determine whether the infant died before or after he was removed from Snively's body, the statement said.
Roberts had been telling friends and family for months that she was pregnant, police said, and had told many of those people, including her live-in boyfriend, that she was carrying twins.
Young said an autopsy was completed on the baby, but he would not release information Monday. Authorities said Sunday the outcome of the autopsy could result in another murder charge against Roberts.
Heidi Kidd, Snively's mother, told CNN affiliate KPTV that her daughter met Roberts on Craigslist, a classified ads Web site, and the two were to exchange baby clothes.
Residents in Roberts' neighborhood told KPTV that she had told them she was expecting a child.
"She didn't appear to be pregnant to us," neighbor Doug King told the station.
Police think Roberts may have had contact with numerous pregnant women in the Portland, Oregon, metropolitan area, the statement said, and police ask anyone who has had contact with her, either in person or over the Internet, to call the Washington County Sheriff's Office.
Roberts' boyfriend is cooperating with police, and has not been charged in the case, authorities said.
Washington County is about 30 miles west of Portland, Oregon.
CNN's Chuck Johnston and Janet DiGiacomo contributed to this report.