Disturbing re scrap values...
Similar thing happened to me - used to live in a flat with the main bike kept upstairs with the rebuilds/ bits in the driveway (dead end, no one needed to go up there). Never any trouble.
Got a nice new shed delvered - everything locked up nicely - all tidied away. Delivery driver just a bit too interested though....
That weekend everything that wasnt bolted down - knicked
'96 Kona Kiluea, GT Zaskar, Bitsa bike, Rockshox, everything.
Found a scummy riding my Zaskar a year later (with new wheels) and politely took it back.
Hope you get it sorted.