Bradley Cooper options work by Lexington’s Rick Beyer

Rick Beyer (second from right) and “Ghost Army” vets (from left): Jack Masey, Seymour Nussenbaum, Nick Leo, John Jarvie, and Gil Seltzer.handout

A decade ago, when Rick Beyer began working on a documentary about a group of artists and designers recruited by the US Army to play tricks on the Nazis, he never imagined it would occupy so much of his time and attention.

He’s glad it did.

“The Ghost Army,” which aired on PBS in 2013, led to a book, which has just been optioned by “American Sniper” producer Andrew Lazar, actor Bradley Cooper, and “The Hangover” director Todd Phillips, and the trio plans to turn Beyer’s true story of inflatable tanks and phony radio transmissions into a feature film.

Written with Elizabeth Sayles, Beyer’s book, “The Ghost Army of World War II: How One Top-Secret Unit Deceived the Enemy With Inflatable Tanks, Sound Effects, and Other Audacious Fakery,” is about the little-known band of brothers who managed to save a lot of Allied lives by fooling the Nazis into believing that their phony battalion was real.

“[Lazar] contacted me a few months ago. He just called me up and left me a message, and we’ve talked a number of times since,” said Beyer, who lives in Lexington. “I’ve not spoken to Bradley Cooper. He’s not on my speed dial and I’m not on his.”

In making the documentary and then writing the book, Beyer says he interviewed dozens of veterans of the secret unit — dubbed “Cecil B. DeMille warriors” — traced their path across Europe, and researched archives. Of the 1,100 men in the unit, only 26 are still alive, he said.

It’s not clear if Cooper will be in the movie, though he’s said he would like to be if there’s a role for him.

“Obviously,” said Beyer, “he should play me as the intrepid investigator looking into the story. But he may not.”