The FBI has launched an investigation into the operations of the city of Maplewood at the request of the police department, Chief Paul Schnell said Friday.

Schnell and other city leaders, however, declined to discuss details of who or what is being investigated to avoid compromising the probe.

"We did request an outside investigation. It is active and ongoing," Schnell said.

The FBI is working with the Washington County Sheriff's Office on the case, Schnell said.

Maplewood Mayor Nora Slawik said Friday that the investigation involved "city operations," but declined to provide further details, saying that doing so could jeopardize the investigation.

"We want full accountability if there's anything illegal," Slawik said.

FBI spokesman Kyle Loven said he couldn't confirm or deny that the FBI is involved.