How a US naval attaché reported from an embassy

Who did a US naval attaché report to in the 1920s and 1930s?

To the ambassador locally, then through a naval hierarchy that included an admiral and intermediary officers rather than directly to the CNO.

The naval attaché served inside a diplomatic mission and therefore reported to the ambassador. Naval information also moved through an admiral and other officers responsible for collecting and assessing attaché reporting. The chain did not normally jump straight from the embassy to the Chief of Naval Operations. That structure connected professional naval intelligence with diplomatic authority and headquarters review before it reached the service's top leadership.