Federal authorities are investigating Charlotte-Mecklenburg Schools, adding a federal probe to several state inquiries into the district’s finances and safeguards for public spending. The U.S. Attorney’s Office for the Western District of North Carolina confirmed Monday that it and the FBI have an active investigation related to CMS. The office said it could not provide further details because the investigation is ongoing. The federal investigation is separate from inquiries by the North Carolina State Bureau of Investigation, the state auditor’s office and the N.C. Department of Public Instruction. The investigations follow the release of documents in September that raised questions about whether CMS officials committed or spent public money without required authorization or other financial controls. The available details do not establish that wrongdoing occurred.