The body of a missing 5-year-old Virginia boy has been found, WSLS in southwest Virginia confirmed.

Noah Terry Thomas' body was discovered in a septic tank near his home after 1 p.m. Thursday, authorities said.

The cause of death hasn't been determined, and no one is in custody. Noah's parents are cooperating in the investigation.

The FBI said it is providing forensics support to the investigation.

Noah had been missing from his home since Sunday morning, when his mother discovered he was gone from their Dublin, Virginia, home, Pulaski County Sheriff Jim Davis said earlier this week.

A heavy police presence was apparent outside Noah's home shortly before 2 p.m. Thursday, according to WSLS.

WSLS reports that crime tape has been put around Noah's home and that a hazardous materials team arrived about 3:15 p.m.

During a news conference Monday, Davis said there was no evidence of foul play, and no one in the area reported seeing anything suspicious.

Teams of officers conducted a ground and air grid search Monday of a one-mile area surrounding the family's home in Dublin, Virginia. Bloodhounds were also used and investigators canvassed the neighborhood.

Davis said Monday that the boy's family was cooperating in the investigation.