The family of a Philadelphia teenager who was killed when staff at a Tennessee treatment center put him into a restraint hold sued the city yesterday, saying the child-welfare agency sent him there despite warnings that the facility was dangerous.

The lawsuit, filed in federal court in Philadelphia, alleges that the city's Department of Human Services and a city-associated mental-health organization acted in "shocking disregard" for the safety of Omega Leach, 17, by not warning Family Court about the "manifestly unsafe and dangerous conditions" at the center.

Also named in the suit were the Chad Youth Enhancement Center, the juvenile mental-health center outside Nashville where the boy was fatally injured June 2, and Universal Health Services, the King of Prussia company that owns it.

The suit contends the company was negligent in its oversight of the two employees who put Leach into the hold after he swung at one of them.

Universal Health Services officials did not return a call seeking comment.

A DHS spokesman said the agency does not comment on pending litigation.

The complaint was filed on behalf of Leach's estate by his mother, Paulette Dolby of West Philadelphia. It notes that a Chad employee called the city in 2005 to warn that Chad workers were using "improper and illegal" force against youths.

While city social workers later stopped short of concluding that unlawful force was being used, they decided that "residents were being harshly and improperly restrained" at Chad. The facility promised to improve.

As The Inquirer has reported about Chad, the suit also notes that a report by city inspectors details how, before Leach's death, a staffer was fired for slamming a child to the ground so hard that the boy fouled himself.

A Family Court judge sent Leach to Chad for mental-health treatment in May after he was arrested for stealing a car.

A month after arriving, Leach argued with a staff member over whether he could stay in his room. The suit alleges that staff members Randall Rae Jr. and Milton Gerald Francis applied a harsh and improper restraint to Leach, and that the fatal injuries were intentional.

In October, a Tennessee medical examiner ruled Leach's death a homicide. Tennessee child-welfare officials also faulted the center for provoking the conflict that led to his death.

No criminal charges have been filed.

Contact staff writer John Sullivan at 215-854-2473 or johnsullivan@phillynews.com.