UPS might have surveillance video in their stores and processing centers. If they’re taking your claim seriously and give a hoot, they should have a security team for these types of incidents.
I would suspect internal theft and deterrence thereof is a big thing for any shipping company. Not to mention false claims which they’d want to disprove. Keep in touch with them for sure, but give them some time if they indicate they’re actively investigating. For 2k insured value, if they do find the culprit they’d likely involve law enforcement.