Prosecutor Linda Evans said she plans to file two murder charges against Effie Goodson, 37, in the slaying of Carolyn Simpson, 21, who was six months pregnant, and the fetus.
A hunter found Simpson's body in a field near Lamar, about 100 miles from Oklahoma City, on Friday. She had been shot in the head, authorities said.
Simpson was last seen on Dec. 22, leaving a tribal casino in Okemah where she worked and Goodson was a patron, Sheriff Houston Yeager said. Investigators believe the two left the casino together.
The next day, Goodson brought a dead fetus that had reached six months gestation to a Holdenville hospital. Goodson claimed to be the mother, but investigators determined she could not have given birth, and she was taken into custody, authorities said.
Goodson had falsely told several people that she was pregnant, going back as far as 10 months, Yeager said. Her husband believed she was expecting, and a shower was thrown for her, he said.
"I think anybody would agree she wanted a baby," Yeager said. "She already had baby items. She was really set up for a baby."
However, investigators have not yet settled on a motive in the slaying, the sheriff said. "We've got a few more questions we haven't got answered yet," he said.
Goodson and Simpson had known each other for about a month after being introduced by family members, he said.
Oklahoma courts have ruled that murder charges can be filed in the killing of a fetus if the fetus was viable — that is, if it could survive outside the womb. Under the state's abortion law, a fetus is presumed viable after the 24th week.