After a box of horse manure was sent to U.S. Treasury Secretary Steve Mnuchin over the weekend, a Los Angeles psychologist told AL.com that they were the one behind it. Robby Strong told the Alabama publication that he sent the manure—which he got from a friend who owns a horse—as a “prank,” and a political expression.

As proof, Strong posted several pictures of himself onto Facebook featuring himself and a box of manure, asking for someone to help document his effort to deliver the manure to Mnuchin. He explained himself by saying, “Because if money is free speech, so is horse shit.”

Strong told AL.com that the act was a “prank” and “political theater.” He elaborated on his Facebook message, telling the publication, “The thing I live by is a rule of transparency and I was exercising my First Amendment rights … when [a Supreme Court ruling] said that corporations are persons and money equals free speech, that is so absurd and my rule of thumb is now that if corporations are free speech, then so is horses***t.”

Secret Service spokesperson Cody Starken told the Associated Press that they were notified by the LAPD after the person said they were the one who sent the package, which was dropped off at Mnuchin’s neighbor’s house Saturday night. Marken wouldn’t identify who the individual is, but Strong said that the Secret Service came to his home on Sunday, interviewed him, but did not arrest him.

“I just got interviewed by the Secret Service and I’ve now joined some of my heroes like Timothy Leary and Martin Luther King,” Strong said.

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