Mr Lindell said he was questioned about a Colorado clerk who was charged in connection with an alleged "deceptive scheme" to breach voting system technology in the US.
“I said to my buddy, I said, ‘that’s either a bad guy or it’s FBI,’” Mr Lindell said on his podcast, The Lindell Report.
Mr Lindell said agents told him they had a warrant to seize his mobile device and ordered him to relinquish it. On a video version of his podcast, he displayed a letter that said prosecutors were conducting an "official criminal investigation for a suspected felony" and noted the use of a federal grand jury.
“Without commenting on this specific matter, I can confirm that the FBI was at that location executing a search warrant authorised by a federal judge,” an FBI representative told the Associated Press.
Mr Trump denounced the Justice Department's actions.
"We are now officially living in a Weaponised Police State, Rigged Elections, and all," Mr Trump wrote on the Truth Social platform.
Mr Trump, whose false election fraud claims Mr Lindell has backed, is currently in a legal battle with Justice Department officials over his potential mishandling of classified records since leaving office last year.
Mr Lindell said he initially believed he was being served as part of the Justice Department's January 6 investigation. Agents told him it was unrelated.
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The Associated Press contributed to this report