Systems and methods for maintaining chain of custody for assets offloaded from a portable electronic device. One exemplary system includes an electronic processor configured to receive, from the portable electronic device, an asset manifest including an asset identifier, a fixed-length unique identifier associated with the asset identifier, and a manifest digital signature. The electronic processor is further configured to transmit to the portable electronic device a storage message based on the asset manifest; receive, from the portable electronic device, an upload completion message; retrieve, from a data warehouse an asset file; and determine, for the asset file, an asset file fixed-length unique identifier. The electronic processor is further configured to determine whether the fixed-length unique identifier matches the asset file fixed-length unique identifier; determine whether the manifest digital signature is valid; and to transmit an asset deletion permission message when identifiers match and the digital signature is valid.