When Leonard Kastle’s debut movie as a writer and director, “The Honeymoon Killers,” was released in 1970, critics raved over the grimly realistic, low-budget, black-and-white crime drama about a lowlife lothario and his overweight nurse lover whose partnership in conning lonely women leads to murder.

French director Francois Truffaut called it his “favorite American film.”

Italian director Michelangelo Antonioni considered it “one of the purest movies I’ve ever seen.”

Kastle, whose first film was destined to be his last, died May 18 at his home in Westerlo, N.Y., after a brief illness, said Tina Sisson, a friend. He was 82.

Kastle is considered one of America’s most intriguing one-shot movie directors.

Neither he nor producer Warren Steibel had any filmmaking experience when they set out to make “The Honeymoon Killers,” which gained cult status in America and Europe.

Kastle was an opera composer whose work had aired on television, and Steibel was the producer of William F. Buckley Jr.’s TV series “Firing Line.”

But after a wealthy friend of Steibel’s agreed to put up $150,000 to finance a low-budget movie, Steibel asked his friend Kastle to write the script.

“The Honeymoon Killers” was based on the true-life story of Martha Beck and Raymond Fernandez, the so-called Lonely Hearts Killers who were executed at New York’s Sing Sing prison in 1951.

The movie was shot on location in and near Albany, N.Y., in eight weeks, with Shirley Stoler and Tony Lo Bianco playing Beck and Fernandez.

The film’s original director was a young Martin Scorsese. But Scorsese’s filmmaking pace was too slow and he was soon removed. Industrial filmmaker Donald Volkman then stepped in for a time before Kastle took over as the credited director.

Like Steibel, Kastle envisioned the movie as a starkly realistic contrast to “Bonnie and Clyde,” starring Warren Beatty and Faye Dunaway.

“I was revolted by that movie,” Kastle said in an interview on the 2003 Criterion Collection reissue of the film on DVD. “I didn’t want to show beautiful shots of beautiful people.”

Kastle vanished from the world of cinema, to the point that two decades later Daily Variety’s Todd McCarthy was telling readers that Kastle was one of the directors about whom people most often asked him, “Whatever happened to?”