Mystery Writers of America (MWA) In Brief Year Formed: 1945 Tax Code Designation: 501(c)(3) (See NCCS) Incorporation State: New York Employer Identification Number: 13-5546742 Home Page: https://mysterywriters.org/ ByLaws: https://mysterywriters.org/about-mwa/mwa-by-laws/ Additional Resources National Center for Charitable Statistics ProPublica Nonprofit Explorer GuideStar