NASHVILLE (AP) — Nashville police on Friday announced that it cost nearly $250,000 to find four teenagers who escaped from a Tennessee juvenile detention facility late last month.

News outlets report that Nashville’s Metro Police wants to send the bill to Youth Opportunity, the private contractor that operates the detention center.

More than 170 officers helped find the teenagers, according to the police department.

A report by Youth Opportunity found that a series of policy violations led to the teenagers’ Nov. 30 escape.

Employees allowed the youths out of their cells after bedtime and then left them unsupervised, it said. Once left alone, the teens got onto an elevator that was improperly left open and tricked the operator into sending them to an unsecured floor. Staff did not immediately call 911, according to the report.

Since then, former detention center supervisor Patrick Jones, 31, and former staff member Alexis Beech, 25, were charged with facilitating the escape by recklessness, Nashville police said in statements. Two other employees were fired for their roles in allowing the escape.

Police spokesman Don Aaron says the department’s costs calculations have been submitted to the city legal department.