An Oregon woman charged with killing a 21-year-old pregnant woman and then claiming the woman's baby as her own had lured her victim to her home through Craigslist.
Authorities believe that Heather Megan Snively, whose body was found in a crawl space in Korena Elaine Roberts' home on Friday, had been using the online classified service to find baby clothes for her unborn son.
An autopsy released Monday said that the death was caused by "homicidal violence," according to Dr. Christopher Young, a deputy state medical examiner.
Snively suffered blunt and sharp force injuries leading to her death, said Young. It was not immediately clear how which injury caused her death.
In a press release Monday afternoon, Sgt. David Thompson of the Washington County Sheriff's Office said that Snively's unborn son was cut out of her stomach after she was killed.
Polcei said Roberts had also been lying to friends and family in the weeks prior to Snively's death that she was pregnant.
"She had told many people she knew, including her live-in boyfriend, that she was pregnant with twins," said Thompson.
Roberts may have been in contact with other pregnant women in the area, said Thompson, who encouraged anyone who has spoken to Roberts to contact their local police department.
The two women had communicated for just under a week leading up to the gruesome murder, police and the victim's mother said.
"Our source is saying that the two women were communicating to buy or trade baby clothes," said Thompson.
Thompson said that while the Craigslist connection has not yet been "forensically confirmed" that it is likely the way that Snively and Roberts met.
Snively's mother, Heidi Kidd, told the Associated Press that she too believed her daughter met her alleged killer on Craigslist. According to Kidd, Snively and Roberts became online friends and then decided to meet in person.
"I guess they decided to meet and I guess that was the wrong thing to do," Snively told the AP. "But Heather's always been a very trusting person."
Alleged Craigslist Baby-Stealer Met Mom-to-Be Before Her Killing
Deon Whitaker, 48, lives on the same block as Roberts and reports having seen Snively at the Roberts residence before the day of the murder.
"It was the same woman who was killed," said Whitaker of the woman she spotted coming out of Roberts' home "sometime in the past month."
"This is a tragedy," she said.
Whitaker described Snively as being visibly pregnant. She said that she never saw Roberts or her boyfriend, but would sometimes see a young boy playing on the couple's lawn.
Snively had been in her third trimester at the time of her death.
Roberts, 27, has two young children who were not home at the time of the murder, authorities said.
Police in Washington County were called to Roberts' home last week after a 911 call reporting a baby in distress was received. The first responders found Roberts, an unidentified man and a newborn child who was not breathing in the bloodied home.
The man has not been charged with any crime, police said.
Roberts told authorities that she had just delivered the baby and was sent to the hospital, where doctors discovered no evidence of her having given birth in the recent past and pronounced the baby boy dead.
"She wasn't dilated," said Thompson.
Roberts, who was arrested and charged with murder, will be arraigned later today, said Thompson. She is currently being held without bail and a lawyer for her was not immediately known. Thompson said that Roberts could face additional charges of murder regarding the unborn baby.
Thompson declined to say if Roberts made any statements at the time of her arrest or during the investigation.
Snively and her boyfriend, Christopher Popp, recently moved to Oregon from Maryland because of a job opportunity. Popp, the father of the child, reported Snively missing, according to Thompson.
While the cause of the baby's death is still not known, Snively's death is eerily similar to past crimes involving pregnant women.
In July 2008, Phiengchai Sisouvanh Synhavong was arrested for allegedly binding together a pregnant woman's hands and feet, removing her baby and stabbing the woman to death. Police in Seattle said that Synhavong claimed that the baby was her own.
Women Stealing Another's Baby From Womb Called 'Desperation'
Earlier that year, two other women in Illinois and Missouri were convicted of similar crimes.
Lisa Montgomery of Melvem, Kan., was sentenced to death in April 2008 after killing Bobbie Jo Stinnett, a woman she met in an online chatroom. Eventually meeting her victim in her Missouri home and cutting Stinnett's baby, then in the eighth month of gestation, from her womb. Police said Montgomery used a kitchen knife to cut the infant from its mother's stomach.
Twenty-six year old Tiffany Hall committed a similar crime, killing her pregnant friend and cutting her unborn child from her womb in a bathtub.
Dr. Michael Welner, a forensic psychiatrist and head of The Forensic Panel, told ABCNews.com that these types of crimes are generally acts of "desperation."
"Characteristically, in the past, cases come up where women kill to establish their fertility," said Welner.
"It's a crime more common in primitive cultures, where women feel the need to establish their mothering identity," he said. "They can't get away with this in hospitals here. They check too thoroughly."
ABC News' Dean Praetorius contributed to this report.