Updated

An upstate New York boy who police say was killed by his parents was mentally and physically disabled and was adopted by the couple years ago.

Chenango (shuh-NANG'-goh) County Sheriff Ernest Cutting Jr. says 16-year-old Jeffrey Franklin had developmental disabilities and had to use a wheelchair. He says the teen was adopted by Ernest and Heather Franklin around 2010.

Fire crews found the teen's body inside the couple's burning home in rural Guildford on March 1. Police charged the couple this week with second-degree murder. An autopsy showed the teen was dead before the fire started.

The cause of death hasn't been released.

The sheriff says the Franklins set the fire to cover up the slaying.

The Franklins have pleaded not guilty, and have been jailed without bail.