Adrianna Iwasinski, News 9 and News9.com

UPDATE -- The Medical Examiners Office has determined Doris and Boyd Haynes both died of smoke  inhalation.  Their deaths have been ruled a homicide.

OKLAHOMA CITY -- Oklahoma City police have arrested a 15-year-old boy in connection with a Wednesday morning house fire that killed an elderly couple.

Tristan Ryan Owen was booked into Oklahoma County Jail on two counts of felony homicide and one count of arson.  Police searched the boy's home Wednesday morning, looking for evidence in the crime. 

Firefighters discovered the bodies of Boyd and Doris Haynes, both 86, when they put out a fire in the 7600 block of S. Miller Street around 4 a.m.

Investigators believe the fire was started by a Molotov cocktail.  Police found glass remnants from a fire bomb that did not ignite near the arrested teen's house.

Police questioned Owen and say they determined he was responsible for setting the fire.

Neighbors describe the Hayneses as a nice couple who'd lived in the neighborhood for years. Their health had started to decline, so on the morning of the fire, they were scheduled to leave the house they'd called home for decades and move into an assisted living center.

Hours before the move, the couple was killed.

Police say Owen lived just down the street from the couple.