American Psycho

I am reading the book American Psycho (published in 1991) and the wealthy business man are repeatedly described as carrying an “attaché”

I know the person who wrote the ransom note (who I think is also the killer and is an intruder) used a lot of movie references. Do we think the maybe read this book, too? It stood out to me and the subject matter would likely interest a sicko.

Thoughts?