The Dunwich Building is a reference to a story by H. P. Lovecraft titled the Dunwich Horror. The holotapes you find are written in a Lovecraftian manner and the "chanting" that Jamies does in the last holotape is clearly inspired by the chanting that Cultists of Cthulhu and the other ancient ones perform. The general feeling of the Dunwich building is also reminiscent of the story "Shadows Over Innsmouth" where the Deep Ones are a species of fishpeople that have sex with the people of Innsmouth (And this ceremony takes place in caves underneath Innsmouth) and have thus made the town into a town of half-men/half-fishpeople inhabitants that kills everyone who comes into town and stays for too long.
If you are interested in more of this, read some books by Lovecraft or pick up the game Call of Cthulhu if you can find it. Scariest game I ever played.