If you suspect or know of an individual or company that is not complying with the tax laws, you may report this activity by completing Form 3949-A. You may fill out Form 3949-A online, print it and mail it to: XXXXX XXXXXX, CA 93888
If you do not wish to use Form 3949-A, you may send a letter to the address above. Please include the following information, if available:
Although you are not required to identify yourself, it is helpful to do so. Your identity can be kept confidential.