The North Carolina father who was working in a two-story-deep dirt hole that collapsed and killed his daughter and her cousin was charged Thursday with two counts of involuntary manslaughter.

Lincoln County Sheriff David Carpenter said Jordan Arwood, 31, was charged following a lengthy investigation.

"This has been a very tragic event and we continue to pray for all persons involved with this as our investigation is turned over to the courts," he said.

At the request of the district attorney, Carpenter said he wouldn't make any additional statements about the case.

Arwood was being held in the county jail on $15,000 bond.

Arwood was operating a backhoe in a pit in April when the walls caved in on the children in the small town of Stanley, which is about 20 miles northwest of Charlotte. The bodies of 6-year-old Chloe Jade Arwood and 7-year-old James Levi Caldwell were dug out the next day.

While investigating, sheriff's deputies removed guns and a marijuana plant from Arwood's home.

After the accident, Arwood was charged with possession of a gun by a felon and making a controlled substance.

Officials described the pit as 20 feet by 20 feet with a sloped entrance leading down to the bottom. The children were at the bottom of the construction site retrieving a child-sized pickaxe when the walls fell in on them. No permits had been issued for Arwood to dig on the site.

In an interview with The Associated Press a few days after the accident, Arwood said he worked frantically to save the children but they were just outside his reach. He says he dug faster and faster trying to save the children until he couldn't breathe.

Investigators say they still don't know why Arwood was digging the hole. But he said he was building a rammed earth home, an ancient building method where dirt is used to shape the foundation.

Arwood said he had been digging the hole for three months.