CHARLESTON, W.Va. -- A Boone County mother suffocated her 4-month-old son to the point of death and then revived him at least 15 times at home and at hospitals in Pennsylvania and West Virginia, police said.Pittsburgh Police Lt. Kevin Kraus said Rachel Nelson, 22, of Costa, tried to suffocate her infant son by holding him tightly to her chest at least twice after he was transferred to the University of Pittsburgh Medical Center's Children's Hospital last week. Nelson had taken the boy to a West Virginia hospital, but he was moved to Pittsburgh on Oct. 18 for treatment of "intermittent respiratory distress," Kraus said. He didn't identify the hospital.Boone County Sheriff Rodney Miller said Nelson may have tried to suffocate the boy an additional 13 times and then taken him to West Virginia hospitals for treatment. Sheriff's deputies were issuing subpoenas Thursday for hospital records in the Kanawha Valley, Miller said.Nelson was taken to Western Psychiatric Institute and Clinic in Oakland, Pa., for evaluation and would be arrested upon release, Kraus said. She faces felony charges of aggravated assault, endangering the welfare of a child and reckless endangerment of another person.The infant remains in the hospital's intensive care unit and is listed in stable condition, Kraus said.UPMC Children's Hospital medical staff found the boy limp with abnormal breathing in the intensive care unit on Oct. 20, Kraus said. Hospital security called police after reviewing surveillance footage from that night showing Nelson allegedly holding the boy moments before.Kraus said police detectives interviewed UPMC Children's Hospital medical staff, Nelson and her husband, Shawn. Nelson admitted to detectives she suffocated her son several times from August through October, including twice at UPMC Children's Hospital.Nelson told detectives she "blacked out" during the incidents. Kraus said she would hold the boy against her chest and tighten her grip when he struggled for air. "He was just shy of death and she would then revive him," Kraus said.Police contacted Child Protective Services in Pennsylvania and West Virginia who seized custody of the infant. Kraus said Shawn Nelson, 43, the infant's father, cooperated with the investigation and would not be charged.Miller said deputies had no previous run-ins with Nelson. She could be charged in Boone County upon completion of their investigation, he said.Reach Travis Crum at firstname.lastname@example.org or 304-348-5163.