TROY, Ohio (AP) — Two teenage sisters died and two other children were hospitalized after a relative found all four unresponsive Friday from a suspected carbon monoxide leak in their western Ohio home, officials said.

Sisters Dionanna Bishop, 14, and Dejah Bishop, 13, died in an emergency room, said Dr. William Ginn, the acting Miami County coroner. He said the likely cause of death is carbon monoxide poisoning.

The other two found at the home in Troy, about 20 miles north of Dayton, were flown to a hospital in Dayton. Troy police Capt. Joe Long identified them as 13-year-old Jakia Jones and 8-year-old Jakari Ward. He said they were in critical condition.

The coroner said the children were believed to be sleeping in the same bed when they were overcome by carbon monoxide from what police officials believe was a malfunctioning furnace or heater.

Long said it is believed the children were all related, possibly cousins, and lived in the house with their grandmother. He said the grandmother had been hospitalized with pneumonia, and the children had been home alone, which is why another relative came to check on them Friday afternoon.

The relative reported that the children had been sick for days and now would not wake up. Police said they hadn't gone to school Friday.