I would have rented this book from a library in the Bethesda/Germantown, MD area in the 1985-1989 timeframe, but I am not sure if it is an 80s book. The details are jumbled, but I want to say it was a children’s fiction book since I would have rented it at age 10-13. I remember someone (a child or adult, not sure?) going in search in a castle for some mystery and eventually finding what looked like the remains, bones, or other evidence of two children behind a tapestry. I think they were 2 brothers, or princes. It seems reminiscent of the “Princes in the Tower” story from the reign of King Richard III in England, but I can’t be sure the 2 stories are related. I am not sure if the word “tapestry” is in the title, but I haven’t been able to locate anything like it anywhere. This has been nagging me for a long time. Thanks for any help you can provide!