Don Johnson in Possible Money Scandal
Johnson, 53, who was traveling with three companions across the Swiss border, was detained for several hours as authorities photocopied all the documents, the New York Post reports.
No charges have been filed, but American tax and custom officials reportedly have been informed.
German authorities have confirmed the actor, who also starred on TV's "Nash Bridges" and in the movie "Tin Cup," is suspected of being involved in a money-laundering ring, according to Britain's Daily Telegraph.
Informing American authorities "wouldn't have happened unless we were suspicious about why he had all these stocks and shares with him," German Customs Investigation Department spokesman Leonhard Bierl told that paper. "This was a lot of numbers."
Speaking to Reuters Wednesday, Johnson denied any involvement. "There is no truth to this story ... It has no merit, no foundation," he said. "They have taken a routine incident and blown it up into this money-laundering ring that supposedly I am involved in, and it has caused me unbelievable difficulty.
"I have had two bank accounts closed. I'm in a new partnership in an investment business, and both of those bank accounts were closed today as a result of this story."