Matter of Locicero, 11 I&N Dec. 805 (BIA 1966) (an individual who had knowingly provided fraudulent information on his income tax returns for two years, by underreporting, was not a person of good moral character).

Note: The Board has found that failure to file tax returns is not necessarily a bar to good moral character, citing Matter of T, 1 I&N Dec. 158 (BIA 1941), Matter of Carbajal, Int. Dec. 2765 (Comm. 1978). Thanks to
Susan Compernolle.