Sao Paulo: A Brazilian judge has issued an arrest warrant for the father and stepmother of a 5-year-old girl who was found dead last week outside a sixth-floor apartment in Sao Paulo.

Judge Mauricio Fossen ordered the couple arrested on Wednesday because police "see them as suspects in their daughter's death", said a court spokeswoman who declined to be identified in accordance with department policy.

Police are treating the case of Isabella de Oliveira Nardoni, who was discovered dead on Sunday morning, as a homicide.

Blood in room

Authorities found blood in her room and a hole in the window's safety netting, and initially said she was apparently thrown to her death.

But preliminary tests revealed on Tuesday that there were marks around the girl's neck and indications in her lungs that she may have been strangled, police inspector Calixto Calil Filho told reporters.

And because her wrist bones were apparently the only ones broken, he said, leading authorities to question whether her death was staged to make it seem like she was thrown from the apartment. Under Wednesday's warrant, the girl's father and stepmother, Alexandre Nardoni Anna Carolina Jatoba, could remain in custody for at least 30 days while police investigate. The court spokeswoman said they would be arrested within hours.

Nardoni told police he left his daughter on her bed to go down to the building's parking lot. He said he locked the apartment's door, but she was gone when he returned.

Neighbours told police they heard a girl yelling "Stop, dad!" shortly before she was found on the ground below the apartment. The father's lawyer, Ricardo Martins, said this may have been misinterpreted.