The parents of a 5-year-old Virginia boy found dead in a septic tank after missing for less than a week have been arrested for child abuse, authorities said.

Ashely White, 30, and Paul Thomas, 32, parents of little Noah Thomas, were arrested Thursday and charged with two counts each of felony abuse and neglect of children, WDBJ reported.

The second abuse charge relates to a 6-month-old baby that was removed from the home a day after Noah went missing March 22.

At the time his mother said she last saw her son that morning watching cartoons in the living room of their home in Dublin, Virginia. After a five-day search, the 5-year-old was found dead March 26 in a septic tank not far from his home.

"No tips or calls led the law enforcement authorities or search and rescue teams to drain the septic tank," Pulaski County Sheriff Jim Davis told WDBJ.

Authorities would not say what led to the arrests of Noah's parents, but they did say an investigation into potential foul play was launched when the child went missing.

A cause of death has not yet been determined and it could take weeks for the autopsy to be complete, Pulaski County Commonwealth's Attorney Mike Fleenor told the station.

"The cause of death will be the critical evidence in this case. At this point, we just don't know what it is," he said.

"Please rest assured that (Davis') office and my office will continue to work together and ultimately resolving and finding the truth of poor Noah's death."

White and Thomas remain held at the New River Valley Regional Jail without bond.