Richard Belzer, best known as Detective John Munch on “Law & Order: SVU,” discusses his conspiracy-theory book at Bethesda Row Saturday. (Sophie Pyle for Bethesda Row)

The TV star climbed onto the small stage outside a shoe boutique in downtown Bethesda on Saturday to a smattering of applause from about 50 fans.

“Here we are in Bethesda, Maryland,” Richard Belzer said musingly. “What is Bethesda known for, beyond the hospital? Is that it?”

Belzer, 68, is not a detective; he just plays one on TV, on the long-running “Law & Order: SVU.” But he’s written a book that trades on that image — “Dead Wrong: Straight Facts on the Country’s Most Controversial Cover-Ups” — and now the star is like any old author, hitting the bookstore/interview circuit to try to sell the darn thing. On a morning TV show in NYC this month, the edgy former stand-up comedian shocked hosts with a sodomy joke and a Nazi salute. So of course, we had to come out to the Bethesda Row Arts Festival to hear him hold forth darkly on how the feds killed Marilyn Monroe and Martin Luther King Jr. But who else would turn out?

Here was the shocker: For every scruffy middle-aged guy with an urgent question about the Bush family’s involvement in the Bay of Pigs, there were probably two women in skinny jeans/cute scarves who really wanted a photo with Belzer — and were not the least bit put off by all this talk of CIA death squads and coverups.

Conspiracy theories: They’re so mainstream now!

Belzer sort of agreed with us. “In the ’50s and ’60s, a lot of people believed in their government, and believed the president was this paternal figure.” Now, “fortunately, the public is ready for anything,” he told us. “They don't trust the government anymore. And they really don’t trust much of the press.”

As usual, he dressed like an undertaker — black coat, black pants, black tie, tinted wire-frames — a look softened by the tiny poodle-terrier he brought along with him. And the mood was somehow light, even amid the dark material.

Why does the government cover up scandals? asked one woman.

“Out of institutional embarrassment,” Belzer said. “So we don’t look like we’re a crazy banana republic to the people in Russia.”

Any theory on the sudden death of conservative rabble-rouser Andrew Breitbart?

Belzer couldn’t see any reason why anyone would want to rub Breitbart out. “It was one of the few times I don’t believe in a conspiracy.”

The wartime death of JFK’s older brother Joe? “There are theories, not that he was assassinated but that he took the suicide mission on purpose. I don’t think he was killed.”

Could the grassy knoll happen today?

“No. They don’t need to kill people today. They have other ways.” He did not elaborate.

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