Prosecutors allege a threatening note left at the Valley Veterans Service Center in Hamilton may have been fabricated.
A court report said Joshua Matthew Getz faces felony charges of tampering and intimidation, and a misdemeanor charge of making false reports to police.
The report said the note said, in part, "You tried to stab someone in the back, and you lost. Watch your back now, you won't see the bullet coming."
The document said Getz told police he believed the note was in retaliation for his testimony against a former center employee in U.S. District Court.
Dan Rachell was accused, then acquitted of making threats against President Obama.
The court document said Getz told police he was concerned for his safety.
Investigators said they found evidence on his computer that Getz, himself, may have written the note.
The report said Getz told police he found the original note, and made a copy of it, but couldn't tell them where the original note was, because he shredded it.