A legal advocacy group has filed a federal lawsuit against the Buckeye Ranch, saying the residential-treatment center denied investigators access to video footage and wouldn't let them speak to children receiving care at the Grove City facility.

Disability Rights Ohio said it had received four reports of improper restraint at Buckeye Ranch in late July and wanted to assess the incidents. Disability Rights is the state's federally designated protection and advocacy system for people with disabilities, including mental illness, and it has authority to monitor service providers and investigate abuse or neglect.

"In the case of Buckeye Ranch, we had video evidence of abuse of the children in their care, which required additional investigation," Michael Kirkman, executive director of Disability Rights, said in a news release. "We call on the court to uphold our access authority so we can investigate and hold accountable those who would abuse some of Ohio's most vulnerable residents."

Buckeye Ranch has indicated it wants to cooperate, but does not believe investigators had cause to demand immediate access to children without the consent of parents or guardians.

According to the lawsuit filed Aug. 16, Disability Rights had been requesting additional video of the incidents -- all camera angles, as well as video of an hour before and an hour after the incidents -- but Buckeye Ranch refused.

Disability Rights announced it would visit the ranch Aug. 16 and wanted to interview the minors in the videos. Disability Rights also informed Buckeye Ranch of its intention "to interview all youth at the facility over the course of the next week," the lawsuit says.

Nick Rees, Buckeye Ranch president and CEO, said his organization asked for time to review the law and make arrangements.

"They basically storm-trooper us," Rees said. "Not only did they say they were coming, they said they're coming at 2:30. Well, it was noon."

Rees said Buckeye Ranch has nothing to hide.

"We have 88 children here. Do we pull them out of school? Out of appointments? So we find ourselves in a dispute, and we say, 'Hey, let's work this out.' And they won't hear of it."

He said Buckeye Ranch will seek clarification from the court on the protection and advocacy law.

Disability Rights often visits public and private programs in Ohio that provide care or treatment to people with disabilities or mental illness, and the advocacy group says it has the authority to do so with little or no notice when necessary.

Disability Rights reported health and safety violations last month at the Heritage of Hannah Neil, a South Side residential program for troubled children. The investigation led state investigators to request that Hannah Neil discharge all residents while the center works on improvements.