A phone tip from an unusual source led cops to an Indiana house where a three-year-old girl was kept in a filthy, bug-infested plywood box.

An Indiana state prison inmate called police to inquire about a young girl being forced to live in a box. That tip led to the discovery, according to Fox News.

When Pulaski County sheriff’s officers executed a search warrant on the house, in the living room they discovered the girl sleeping in the closed 24-inch by 24-inch box, which smelled of urine and was covered in dead bugs.

“It’s one of those deals, you go there and think, ‘Hopefully, this is not true,’” Pulaski County sheriff Jeff Richwine told reporters. “Nobody’s going to have a small girl in a box, that’s just not going to happen ... You’re thinking, ‘My God, who would do this?’”

Nine people, including the girl’s father, 25-year-old Christopher Short, and his 42-year-old wife Donna, were arrested. Court documents show they told police the girl would climb into the box, which had a metal eye that could be locked, without their prompting but other children in the house indicated otherwise.

The girl was allegedly kept in the box for extended periods of time during the evening.

Incredibly, none of the people in the house when cops arrived mentioned the girl in the box, Richwine added.

“Even while we were in there and started taking people out, nobody spoke up and said, ‘Hey, there’s a little girl over here in a box,’” he said.

The girl’s maternal grandfather, Frank Jackson,told WNDU he was appalled at how the child was treated.

“I’ve seen people treat their animals better,” he said. “It’s like a nightmare and I wish I’d wake up,”

The girl’s parents have both been charged with neglect of a dependent, along with Patricia Meeks, 18. Six other adults were charged with failure to report child abuse.