Was using those md5 sums on images for flagging images 20 years ago for the government, occasional false positives, but the safety team would review those, not

Was using those md5 sums on images for flagging images 20 years ago for the government, occasional false positives, but the safety team would review those, not operations. My only role was to burn the users account to a dvd (via a script) and have the police officer pick up the dvd, we never touched the disk, and only burned the disk with a warrant. (we never saw/touched the users data...) Figured this common industry standard for chain of custody for evidence. Same with police videos, they are uploaded to the courts digital evidence repository, and everyone who looks at the evidence is logged. Seems like a standard legal process was followed.