When documentary filmmaker Dan Klores came upon Mark Fass’s article about Burt Pugach and Linda Riss (“A Sort of Love Story” in The New York Times of March, 2004), it rang a bell.

“When I read that,” Klores said at a recent Dallas interview in conjunction with a screening of his film “Crazy Love” at the USA Film Festival, “it reminded me of the story. I was nine or something [when it happened], and it brought it back.” Pugach, a combative lawyer, had been romancing the younger Riss for some time, but she’d dumped him when she discovered he was married, and he decided that if he couldn’t have her, nobody would. He actually hired a hit-man to attack Riss, but though their tale is a twisted one in many respects, the two eventually wound up together.

“I was going to call the reporter,” Klores recalled, “but I said to myself, ‘Let me take a shot,’ and I looked through the phonebook.”

And he found a listing for Pugach. “I called him out of the blue,” Klores said, “and then I went out to lunch with both of them at a diner. And I brought a friend with me, an actress, because I wasn’t going to do it as a documentary at first. I had some weird ideas. What excited me about it was the idea of obsession, the idea that when we get hurt and are in need, how obsessive we become. So I had the idea of trying to do a hybrid of a film—somewhat of a documentary, but I’d work with a writer and write scenes as if it were a feature. And then cover the actors who were playing their roles, and how obsessed they become with their roles. It got too complicated. But then I started to meet more and more people involved in their story and said, ‘Okay, let me just do it as a documentary.’ First I was interested in the obsessiveness, but then I said, no, it’s a story about what we do when we’re hurting, what we don’t talk about, what we’ll do not to be alone.”

Klores dove into the investigative work that’s always required in documentary work. “The detective work was intense, but it was sort of fun,” he recalled. “I actually hired a private detective agency—Giuliani’s firm, ex-New York City detectives—to help me find some things. From the detectives I was able to get all the police and court records. I couldn’t keep them, so I’d have to go up into the courthouse for weeks and take notes and make copies.”

But what makes “Crazy Love” so special are the interviews—with friends, journalists and officials, but especially with Pugach and Riss themselves. Pugach overlooks some of the things he’s done in an almost staggeringly blithe tone. But Klores wouldn’t call him defensive.

“You can say a normal person is defensive,” Klores observed. “But he’s not a normal person. He’s been diagnosed as a psychopath, and he is. So he’s not defensive—he’s without conscience. That was evident from the first time I met him, at that lunch in the diner. She came with him. And I’m taking off her coat, I’m buttering her toast. He just talks about himself.”

And Riss is an equally intriguing case. “She’s connected to him in a way that’s obviously strange,” Klores said. “That’s what the movie’s about. Her defense of him—she’s so damaged that she means it now. When she defends him, she means it. The only one that sees her the way she sees herself is him.”

It’s “Crazy Love” indeed, and Klores’s film captures it and surprises you along the way.