Legendary former New York City homicide detective Beau Dietl said Saturday that he was "shocked" by reports that Sen. John Kerry participated in a 1971 Kansas City meeting of the Vietnam Veterans Against the War where a plot to assassinate seven U.S. Senators was considered.

"I was shocked listening to the story," Dietl told WABC Radio's Monica Crowley, who had just broadcast an update by the reporter who broke the news last week, The New York Sun's Thomas Lipscomb.

"I like John very, very much as a person," said Dietl, who's a personal friend of the Massachusetts Democrat. "But if this has any validity to it, it could be earth shattering."

Dietl said Kerry may have committed a crime if he took part in any discussions about the assassination plot.

"When you talk about killing somebody that's conspiracy to commit murder," he told Crowley. "At the point you talk about it you're guilty of a crime."

Dietl said it made no difference whether or not the plot was carried out, telling Crowley, "By just talking about it, it's the crime of conspiracy."

The former lawman, who now operates his own security firm "Beau Dietl & Associates," urged his old friend to come clean about the 1971 episode, warning, "Once they start to cover things up, that's when the crimes are going to start to begin again."

Dietl went out of his way to assure Crowley that, despite his comments, he has a warm relationship with the likely Democratic nominee, explaining, "John Kerry is a friend of mine. He was at my birthday party. I was at Mara Lago with him last year and he's a good person."