In 1981, Koper played an uncredited role in the production of John Waters' film
Polyester, arranging financing from other investors as well as investing his own money, with which he trusted Waters "like an old penny-pinching aunt." He also helped Waters develop the concept of the scratch-and-sniff Odorama cards distributed to the audience. On April 15, 1983, Koper read
Vincent Musetto's now famous headline in the
New York Post: "Headless Body in Topless Bar." The headline inspired Koper to begin writing a screenplay loosely based on the facts of the story, with the headline as its title. Remembering the years that followed, Koper said, "If my life were a newspaper, this would be splashed on page one: 'Screenwriter Haunted by Headless Headline.'" and collaborated again with Bruce to realize it.
Headless Body in Topless Bar opened in New York and Los Angeles to mixed reviews.
Stephen Holden of the
New York Times credited the cast's "fine ensemble acting" with "disguising the screenplay's long-windedness." Bob Strauss of the
Los Angeles Daily News described the film as
Paul Verhoeven's "
Showgirls without the budget," criticizing both the screenplay produced by "Koper's tabloid ink-stained hands," and Bruce's "uncertain direction." John Anderson of the
Los Angeles Times compared the film to
Lifeboat and
No Exit, "but without a certain delicacy."
David Stratton of
Variety described the film as "gripping," praised Bruce's "fluid direction" and predicted that "prospects look brighter for video release."
Körper ohne Kopf in Oben-ohne-Bar, German dramatist Klaus Pohl's
German translation of Koper's original script for the stage, premiered at the
Deutsches Schauspielhaus in
Hamburg, Germany on 11 November 1999. One reviewer found the play "reminiscent" of Quentin Tarantino films. In 1996, Koper took up seasonal residence in the
Long Island hamlet of
Springs, New York, where he became interested in the story of the four
Nazi saboteurs who disembarked from a
U-boat on the morning of June 13, 1942, to land on
Amagansett's Atlantic Avenue Beach, then boarded the
Long Island Rail Road bound for
Manhattan as part of a
plan to attack the United States. A
Coast Guardsman foiled the plot; upon encountering the invaders, he ran back to the Amagansett
Coast Guard Station and raised the alarm, "The Nazis have landed!"
Medienboard Berlin-Brandenburg commissioned Koper to write a screenplay about the Nazi misadventure, entitled
Code Name: Pastorius. Koper said he relied on the military trial transcripts housed at the
National Archives to fully understand the story, and tried to capture the story's inherent dark humor. Koper won the 2001
Santa Barbara International Film Festival's Peter Stark Screenwriting competition for his screenplay
Joyful Noise. In 2016, Koper wrote and co-produced the documentary
Trump Tribe, filmed at that year's
Republican National Convention in
Cleveland, Ohio, and featuring seventeen voters who speak candidly about their zeal for the presidential candidacy of
Donald Trump. The film uses the "formal structure of anthropological study to divide Trump supporters into groups such as Myth Keepers, Tribal Women, Tribal Elders, and Tribal Youth." ==Filmography==