Arson investigator is unclear on source of fatal Oklahoma City house fire

Tristan Owen, 17, is accused of setting the fire that killed Boyd Haynes, 87, and his wife, Doris Haynes, 86. The couple died of smoke inhalation July 13, 2011, a few hours before they were set to move to an assisted living facility.

Owen is charged with two counts of first-degree murder and one count of first-degree arson. If convicted of murder, he will be sentenced as an adult and could spend the rest of his life in prison.

Prosecutors allege Owen started a fire in a trash container outside the couple's garage, which spread to the structure of their south Oklahoma City home.

Neither investigator, though, could link burned pajama pants found on the defendant's property and remnants of two Molotov cocktails found in front of his house, with the trash can fire.

“Something ignited the trash can, which ignited the house,” Oklahoma City fire Maj. Scott Dallas testified.

“Do we know what that something is?” defense attorney Francis Courbois asked Dallas.