What do you mean? He knowingly helped two undercover agents lie who disclosed crimes to him. One that supposedly smuggled drugs and another who touched a 14 year old. If he immediately severed contact when they confessed to these crimes he would be free. If you are doing something in a gray area make sure you dont make mistakes.
Here is the witness tampering law: "(c) Whoever corruptly—...
(2) otherwise obstructs, influences, or impedes any official proceeding, or attempts to do so,"[1]
First Crime: "On Oct. 15, 2012, Williams got a call from a man named Javier Domingo Castillo. He told Williams he was a Department of Homeland Security inspector who’d helped a friend smuggle cocaine into the country."
He helped him beat a lie detector test knowing that he committed a crime. Now I would assume being administering a lie detector test is a "preceding before an executive department."
From wikipedia on witness tampering (this is what he was charged with): "Witness tampering is the act of attempting to alter or prevent the testimony of witnesses within criminal or civil proceedings. Laws regarding witness tampering also apply to proceedings before Congress, executive departments, and administrative agencies."
Police in the US are allowed to lie or use deception to get someone to get a confession.
Here is the witness tampering law: "(c) Whoever corruptly—... (2) otherwise obstructs, influences, or impedes any official proceeding, or attempts to do so,"[1]
[1]https://www.law.cornell.edu/uscode/text/18/1512
I'm guessing a lie detector test is an Official Proceeding.