A smartphone can create different procedural traces. The authority may retain the original device, create a technical copy, analyse individual data or place files in the investigation file. Return of the original therefore says nothing by itself about the further handling of data.
A data copy should be addressed through precise questions: Was an image or another copy created? Which periods, apps or file types were analysed? Which data was taken into the evidence file? Do working copies still exist and what purpose is said to justify them? The answers should be verifiable from the file or an authority notice.
A copy can be offered to avoid retaining the entire smartphone where it reliably fulfils the securing purpose. Whether it is technically and legally sufficient depends on the purpose, evidentiary reliability and protection of third-party or particularly confidential data. It would go too far to say that every forensic copy must automatically be returned or deleted.
Return, disclosure of a data copy and deletion are therefore three different requests. A clear staged formulation is useful: first request return of the device, then ask for information about copies and analysis, and finally seek a separate assessment of continued retention or deletion.