A St. Pete mother was charged with first-degree murder Wednesday morning after she allegedly accused her 4-year-old son, according to police.

Officers arrived at the scene around 3:30 pm after the boy's sister, from Sixteen-year-old Finley Cullom came home from school to find his mother, Diana Cullom, 43, holding his brother, Finley Cullom, in a bed. There was blood at the scene and throughout the house. “He walked into the house, saw blood everywhere, saw his 4-year-old brother…,” St. Petersburg Police Chief Anthony Holloway told WFLA. According to police and court records, Cullom suffocated Finley with a plastic bag. Police say she inflicted non-life-threatening stab wounds on herself and was taken to Bayfront Hospital. Those wounds were visible on her arms when she first appeared in court Wednesday after being charged with her son's murder. Police initially said the boy was stabbed to death, but Wednesday morning the medical examiner determined he had no stab wounds and had been asphyxiated. St. Petersburg Police Chief Anthony Holloway said the 16-year-old also found a knife and a note at the home located at 1700 Tanglewood Drive Northeast. “We believe the note was left by Mom,” Holloway said during a news conference Tuesday night. The exact contents of the note were not specified, and police still do not know the mother's mental health history. According to authorities, the child's father was not home at the time of the incident, according to Fox 13. On Wednesday, a judge informed Cullom, who remained expressionless with her arms crossed in court, that she will remain in jail without bail. He also instructed her that she cannot have any contact with her 16-year-old daughter.