A young girl returned home from school on Tuesday afternoon to encounter a devastating scene: her 4-year-old brother lifeless in their blood-soaked mother’s embrace on a bed, according to authorities in Florida.

The St. Petersburg Police Department reported that 43-year-old Diana Elizabeth Cullom allegedly used a plastic bag to suffocate her son, Finley Cullom. She now faces charges of first-degree murder.

“The girl walked into the house and was confronted with blood everywhere and her deceased younger brother,” Chief Anthony Holloway explained to reporters, leaving little room for doubt about the situation’s grim nature.

Police were called to a residence on the 1700 block of Tanglewood Drive NE around 3:30 p.m. in response to a report of someone bleeding. Upon entering, they discovered the boy had died, and his mother appeared to have inflicted stab wounds on herself. Emergency services transported Cullom to a hospital for treatment of injuries deemed non-life-threatening. She has since been released and is currently held at the Pinellas County Jail.

Initially, due to the extensive blood found at the scene, investigators suspected that Cullom had stabbed her son. However, further examination revealed that Finley had been suffocated with a plastic bag. Investigators also uncovered a note believed to be written by Cullom, though its contents have not been disclosed.

After receiving her Miranda rights, Cullom gave a statement to the authorities, but details from that statement have been redacted from the police report. The motive behind the tragic act remains unclear, as law enforcement has yet to disclose the reasons behind the killing.

Cullom’s husband, a local dentist, was not at home at the time, police say. Cullom helped her husband start Crescent Lake Family Dentistry, according to her biography. They had four children together.

“In her free time she loves to spend time with friends and family, including her seven siblings, time with God, construction, fishing, architectural design and renovation projects, gardening, business ventures, charity work, travel, reading/research, music festivals and almost any outdoor activity,” the biography said.