Authorities are investigating the death of a 15-year-old boy who was found unconscious Monday morning outside a north Forsyth home.

The investigation began about 8:30 a.m. after Forsyth County Sheriff’s deputies responded to reports of an unresponsive teenager lying in the back yard at 9035 Walnut Cove Court.

The teen, identified as Trey Scott Spencer of Fairlane Trail, was taken to Northside Hospital-Forsyth, where he was later pronounced dead.

According to a Forsyth County Sheriff’s report, Spencer was a student at North Forsyth High School.

His body has been sent to the Georgia Bureau of Investigation’s Crime Lab in Atlanta for an autopsy.

Authorities are not saying how Spencer may have died.

According to the report, Spencer had been hanging out the night before with a 14-year-old boy who lived at the house on Lake Lanier.

The younger teen told authorities they had been drinking bourbon, smoking marijuana, huffing dust cleaner and taking Klonopin, a prescription medication commonly used to treat anxiety.

According to the report, the friend said his 18-year-old sister told him to come inside about 10:30 p.m., at which time he thought Spencer had left. The next morning, the 14-year-old found Spencer lying in his yard.

Robert and Laura Lancaster, the parents of the siblings, returned home about 6 a.m. Monday from a trip to St. Simons Island.

According to the report, the 14-year-old told his father that Spencer was in the backyard and they called 911.

As part of their investigation, authorities searched the home and reportedly found a dead animal, feces, bugs and other debris inside.

Robert Lancaster, 46, and Laura Lancaster, 52, were arrested and charged with second-degree cruelty to children.

“The charges are due to the deplorable conditions of the inside of the home,” said Sheriff’s Capt. Tim House.

The couple is being held at the Forsyth County Detention Center without bond.

Their children were turned over to family members.