The influence of Errol Morris on American documentary filmmakers is all to evident in Jeff Prosserman’s “Chasing Madoff,” which isn’t about the notorious Wall Street swindler so much as it is about Harry Markopolos, a man who early on decided that the fund manger was a fraud and became obsessed with unmasking him. The focus on so single-minded and driven an individual, and the combination of interview segments and flashy visual supplements (including fancy recreations) are all reminiscent of Morris’ idiosyncratic style. Even David Fluery’s background music is similar to the work of Philip Glass, who scored several of Morris’ films.

Morris is a great model, of course—he’s made some of the most extraordinary documentaries of the last two decades. But he’s developed a very personal approach, and his mimicking of it makes one wonder whether Prosserman has a style of his own.

Still, his film certainly has an oddly compelling fellow at its center. On the one hand, Markopolos has the makings of a heroic whistleblower. He’s also a David taking on Goliath, in the form not only of Madoff but also the SEC, which he tried repeatedly to warn about the chicanery of the man. But there were simply too many powerful people whose interests would be harmed if Madoff were brought down, so Markopolos was ignored by the establishment. And though he’s been feted after the fact for having discovered Madoff’s malfeasance long before anyone else, he considers himself a failure for not having succeeded in bringing him down. After all, Madoff surrendered to authorities only after the economic collapse of 2008 made his position untenable. It wasn’t until afterward that Markopolos’ proof of his wrongdoing was vindicated.

But what makes Markopolos an interesting subject isn’t just his obsessive character; it’s also his proclivity for melodramatics. As his interviews make clear, he became convinced as his work went on that he’d become a marked man, and that he and his family were in danger. He armed himself, took shooting lessons, checked for bombs under his van every time he drove it, and imagined how he and his family might be killed by intruders any night.

It’s here that Prosserman crosses the line—not by recording Markopolos’ fears, but by “reenacting” them, although in this instance what’s being shot isn’t what happened but what Markopolos worried might happen. Morris tweaked his reenactments in repetitions to suggest the vagaries involved in trying to apprehend the truth about the past, but here we have Prosserman reenacting something that never happened, except in his subject’s imagination. Whether that’s an appropriate device is very questionable.

But setting aside those sorts of methodological problems, as a whole “Chasing Madoff” is a compellingly watchable film, simply because Markopolos is such a weird mixture of the admirable and the unnerving, a guy you have to respect for what he tried to do but seems the sort of person who’d be impossible to put up with for long. To be sure, his colleagues Frank Casey and Neil Chelo, who together with Markopolos narrate the story, speak of him in glowing terms, but one notes a trace of amusement as they do so.

Some other elements of the picture are less engaging. Overuse of excerpts from the Washington hearings where Markopolos testified and congressmen excoriated SEC officials and periodic footage of victims of Madoff’s scams, identified only by their account numbers, bemoaning their very real losses, for example, are the cinematic equivalents of gilding the lily.

So if you want a factual primer on Madoff’s crimes, you should look elsewhere. But as a portrait of an unusual man, “Chasing Madoff” is flawed but fascinating.