WASHINGTON — The last time Secret Service agents escorted a U.S. leader to face criminal charges, they kept their mission a secret — even from their own bosses.

It was Oct. 10, 1973, and just a few agents knew the history they would make in ensuring that Vice President Spiro Agnew appeared in a federal courtroom to enter a plea and resign from office.

“It was a big day for the country, and a sad day,” said Jerry Parr, one of those agents, in a 2010 interview. “And we didn’t tell anyone it was happening. For better and worse.”

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