A St. Petersburg mother accused of suffocating her 4-year-old son appeared in court for the first time Wednesday, where a judge ordered her held without bail.

ST. PETERSBURG, Fla. — A St. Petersburg mother accused of killing her 4-year-old son is being held without bail following her first court appearance Wednesday.

Police say 43-year-old Diana Cullom suffocated her son, Finely Cullom, with a plastic bag inside the family’s home on Tanglewood Avenue NE. Officers were called to the home around 3:30 p.m. Tuesday after Cullom was found with self-inflicted stab wounds, holding the child.

Cullom appeared in court by video and faces a charge of first-degree murder. A judge ordered her held without bond.

The child was discovered by the couple’s 16-year-old daughter when she returned home and found blood throughout the house, according to St. Petersburg police.

“When the daughter got home, there was blood all over the house and she found her mother holding her 4-year-old brother, and they’re both covered in blood,” police spokesperson Yolanda Fernandez said.

Initially, police said the child was stabbed. Fernandez says officers on scene saw the child was covered in blood and determined he was deceased. 

“At that point detectives had to back everyone out of the house in order to get a search warrant in order to do the forensic examination of the scene and to allow the medical examiner to go and examine the body,” Fernandez said. “That didn’t occur until late, late that night, around 11 p.m.”

Once the medical examiner got on scene, they determined Finley did not suffer any stab wounds but instead died from suffocation.

Investigators say Cullom’s stab wounds were self-inflicted and were visible as she raised her hand during the court hearing. Her husband, Damian Cullom, was in the courtroom gallery, watching the proceedings.

Police say they have never responded to calls at the home. Online records show the house was listed for sale one day before the killing. Authorities have not confirmed whether mental health issues played a role.

“A situation like this is really difficult to predict,” Fernandez said. “It’s not tied to criminal activity or drugs or anything. When you have crimes like this, that are domestic in nature, that are hard to understand or explain, it can happen anywhere.”

There was no answer Wednesday at Crescent Lake Family Dentistry, a practice owned by the Culloms.

An adult daughter of Cullom told 10 Tampa Bay News the family does not wish to comment at this time.

Cullom remains in jail as the investigation continues.