Government officials and LEO's are 'allowed to lie'* to the public, regardless of Smith-Mundt act.
https://www.law.georgetown.edu/american-criminal-law-review/wp-content/uploads/sites/15/2018/04/55-2-A-Double-Standard-in-the-Law-of-Deception-When-Lies-to-the-Government-Are-Penalized-and-Lies-by-the-Government-Are-Protected.pdf
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or at least face no legal consequence for lying under certain circumstances - see Article I, Section 6, Clause 1 of the U.S. Constitution