The Borgov Crypt (Boyar's Crypt) is in the cemetery east of the Town of Mordavia. You can get into it by using an Open spell, pick its lock with a Thief's Toolkit (QFG4) or later on just use a key which Igor gives you if you help him. Many of the Borgov's bodies lie there and there is also a carved Grim Reaper's statue. There is also a secret passage to the Castle Borgov.
Behind the scenes[]
Originally there was a way to encounter a Crypt Wraith.