Use magnifying glass to check knife for fingerprints.

Suppose now is a good time to investigate this knife. You combine the three items, looking at the knife through the magnifying glass and comparing any markings to the fingerprint. First thing you see is a code: CCC-0402. It's clearly stamped on, possibly a serial number or production code? Continuing to inspect it, you strike gold. A fingerprint, clearly matching the one from the computer. Whoever it was that swiped the computer had the knife at some point.