UPDATE!
So I received a call from my insurance company the other day. The police arrested a guy for breaking & entering, and when they searched his property, they found "a lot of Lego sets". One detective was having lunch with my detective and casually mentioned the find, and he remembered my case from 2016 and they interrogated the suspect. He totally admitted meeting me on Craigslist, bought a few sets from me, and then came back to my warehouse to commit the robbery.
He was able to back a cargo truck up to the loading door and spend several hours loading up. The replacement value at the time was $39k.
I am so relieved they caught the guy, and now I'm waiting to hear from the police so I can go see what is left from the theft (they say there is A LOT).
Next step will be to strike a deal with the insurance company to purchase everything back (at a salvage rate of course). They are willing to give me the right of refusal so I can recover all or some of it.
I'll update once I see what is left and what we can work out.
Just a reminder to everyone who can learn from my ignorance & innocence: never let anyone into the inner sanctum. Since the theft, we treat the warehouse like Willy Wonka's factory : no comes in, no one goes out. We even have a visual barrier separating the storeroom area from being seen by UPS and FedEx drivers. As far as Craigslist goes, I've only tried to sell a handful of larger items (new MF for example) with the stipulation that the transaction takes place at the local police department, and I haven't had a taker yet.