20 CFR §10.529

1. (a)If an employee knowingly omits or understates any earnings or work activity in making a report, he or she shall forfeit the right to compensation with respect to any period for which the report was required. A false or evasive statement, omission, concealment, or misrepresentation with respect to employment activity or earnings in a report may also subject an employee to criminal prosecution.
2. (b)Where the right to compensation is forfeited, OWCP shall recover any compensation already paid for the period of forfeiture pursuant to 5 U.S.C. 8129 and other relevant statutes.