here's the pdf in the fbi vault, can't do a search so you'll have to manually look. let us know if you find it.
https://vault.fbi.gov/the-finders/the-finders-part-01-of-01/view
[–] 21092602? 0 points 1 point 1 point (+1|-0) ago
It detailed the size and dimensions of the tunnels, where and what directions the tunnels led to, dimensions of the rooms that were connected to the tunnels, some artifacts they found in the tunnels, etc.
It looked like a report prepared by investigators that inspected the tunnels/rooms personally. The document also said that the tunnel DID extend to the business next door's bathroom. The bathroom had a hole cut through the floor that was back filled. The document states it is obvious that the rooms and tunnels were hand dug.
The document also stated that due to extreme time constraints, they could not explore the entire tunnel system or sift through all the debris found.
[–] 21090973? 0 points 1 point 1 point (+1|-0) ago
I just looked it up. The diagram with tunnels starts on pdf p.48 and there are memos that follow re: McMartin Preschool.
https://vault.fbi.gov/the-finders/the-finders-part-01-of-01/view