Now authorities are investigating after the rain-soaked walls of the pit collapsed Sunday, fatally burying two young cousins, including Arwood's daughter.
Arwood, 31, was operating a backhoe Sunday night in the pit when the walls collapsed and he called 911.
Arwood's desperate voice is heard on a recording released by the Lincoln County Sheriff's Office on Monday, when the children's bodies were recovered.
"Please hurry ... My children are buried under tons of dirt ... They're buried under tons of clay ... It fell on top of them," he said sobbing.
When the dispatcher asked him if he could see the children, Arwood said he couldn't.
"The entire wall collapsed on them. Get a crane. Get a bulldozer. Get anything you can, please," he said. "There's no way they can breathe."
As the dispatcher began encouraging him -- and with people wailing in the background -- Arwood began praying.
"Lord lift this dirt up off these children ... so the children will be alive and well ... I have to get my kids. Lord, please," he said.
The bodies of the two young cousins, 6-year-old Chloe Jade Arwood and 7-year-old James Levi Caldwell, were dug out Monday morning.
Later on Monday, sheriff's deputies removed firearms and a marijuana plant from Arwood's mobile home. Arwood is a felon who is not allowed to have guns. He was convicted in 2003 for possession of a controlled substance with intent to sell.
The father had been digging with a backhoe on the site Sunday, Sheriff David Carpenter said. Investigators described the pit as 20 feet by 20 feet with a sloped entrance leading down to the 24-foot bottom. The children were at the bottom of the pit retrieving a child-sized pickaxe when the walls fell in on them, Carpenter said.
The sheriff would not say what Arwood was building or whether he had any professional help. He did say that investigators would be looking into reports from neighbors that Arwood had been building some sort of protective bunker.
"They were so distraught we hope to be able to talk to them today and come up with some information on that," Carpenter said. "It's a very large hole. It would look to be something like that, but I don't know. ... We're going to find out exactly what his intentions were."
He said deputies would be speaking with county planning and zoning officials about any potential building code violations at the site.
Andrew Bryant, a planner with the Lincoln County Planning & Inspections Department, said no permits had been issued.
On the tape, Arwood said he didn't know what happened.
"They were inside the hole helping to get something and the wall collapsed," he said.
At one point, the dispatcher warned him not to put pressure on the dirt. But Arwood said he had to reach the children.
"If this was you and your children in the dirt, you'd be moving the dirt, too," he said.
Arwood's house was at the end of a gravel-covered road dotted with modular and mobile homes. It's a tight-knit rural community where neighbors sit outside on front porches and look out for each other.
When word spread about the disaster, they ran to Arwood's house and began helping. On Monday, they were somber, saying they were heartbroken for the family. They said Arwood told them it happened without warning and that he tried to grab the children, but they were just beyond his reach.
It was no secret that Arwood was digging a two-story deep hole. Neighbors said it wasn't unusual to see children in the pit when the girl's father was working there.
Neighbor Bradley Jones, who works in construction, said there was no structure to support the pit's tall dirt walls and that there was some concrete on a ledge on top of the hole.
In recent days, the hole was muddy from the rain. He said he warned his daughter, Chelsea, who babysits for the children, not to go in.
"It was dangerous. There was nothing to reinforce those walls," he said.
Chelsea said Arwood told her that he was building the structure to "protect his family" -- it was going to be a bunker.
"It's so sad," she said.
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