A teenage girl arrived home from school Tuesday afternoon to a horrific scene: Her 4-year-old brother dead in their bloodied mother's arms on a bed, Florida cops say. The St. Petersburg Police Department said 43-year-old Diana Elizabeth Cullom suffocated Finley Cullom with a plastic bag. "She walked into the house, she sees blood everywhere, she sees her 4-year-old brother … you come to the conclusion," Chief Anthony Holloway told reporters. But further investigation revealed she allegedly suffocated Finley with a plastic bag. Cops also found a note reportedly written by Cullom in the home but they did not divulge what it said.