“American Murderer” is a workmanlike “true crime” thriller about the hunt for con-man turned accused killer Jason Derek Brown.

Writer-director Matthew Gentile’s feature debut, following a short film he did on the subject, attracted plenty of talent — with Ryan Phillippe as the FBI agent leading the chase, and Idina Menzel, Jacki Weaver, Paul Schneider, Kevin Corrigan and Moise Arias in support of “Ozark” and “Outer Range” veteran Tom Pelphrey as the lead.

But what was made from that compelling subject and with this impressive cast is a story that lacks excitement, the suspense of a cat-and-mouse tale or anything remotely emotional. It’s a film as dramatically-flat as its desert southwest settings.

We meet Brown as he preps for a “performance” on a November night in 2004. He’s got to get his game face on, get off script and convince a pawn broker to give him lots of cash for a couple of watches he’s hocking. He may roll up in an Escalade, but the hoodie, the sad face and the sad story have to do the heavy lifting.

“My dad gave me” this Rolex, and — tears this time — “my Mom” just passed, and this was her watch, and on and on he goes. Of course he can turn off the waterworks in a flash when the hard bargaining kicks in. The pawn broker doesn’t react to any of this, or the hasty “You got a back door?” at the conclusions of sale. And the broker doesn’t see the cackling Brown does at conning another sucker, and at dodging the guys who follow him into the shop because he owes them and everybody else money.

The FBI is on this case because of what we can figure out from the film’s title, that this con-man, thief and hustler crossed one last line at some point. Phillippe plays the unemotional agent in charge, and the film is a series of flashbacks taken from interviews with people who knew the suspect.

Menzel plays a landlady, single mom and sometime lover, who denies any “intimate relationship.” Schneider is the suspect’s increasingly put-upon and put-out brother, Weaver is the mother who’s decided “You’re some actor, you know that?”

And Shantal VanSanten plays the sister who suggests that their childhood and their sketchy Dad (Corrigan) are the reasons Jason turned out the way he did.

But as we see Brown living it up, over-dressing, buying boats and confidently closing down the strip clubs, two things stand out. Pelphrey is really chewing the scenery in this performance. And there’s an awful lot of interesting detail that would have added color to this generally colorless film, things briefly mentioned and never shown.

Jason grew up Mormon? He was married? Something in him “snapped?” His Dad disappeared? It’s like half the movie is missing.

We’re simply dropped into this cruel hustler’s hustles — hitting family up for money, partying like mad, cozying up to Melanie (Menzel). The storytelling format the filmmaker has chosen seems to want to limit us to only the information the FBI man gleans from those he questions. But that “rule” limiting what he knows and what we know robs the film of anything that could humanize the guy or his victims. And besides, there are places Gentile breaks his own rule.

The narrative begins with a half-interesting transaction and get-away, and choppily jumps backward and forward, leaving so much connective and potentially compelling material out that the film feels incomplete.

Pelphrey’s performance leans towards repellant, and with Phillippe doing a Joe Friday deadpan, we only have the characters surrounding them to grab hold of and identify with.

That points to one last thing Gentile left out, a charismatic and cunning quarry for us to focus on, root against and stick with as this “American Murderer” is pursued through his life of crime.

Credits: R for pervasive language, drug use, some sexual content/nudity and violence.

Cast: Tom Pelphrey, Idina Menzel, Jacki Weaver, Paul Schneider, Shantal VanSanten, Kevin Corrigan, Moises Arias and Ryan Phillippe.

Credits: Scripted and directed by Matthew Gentile. A Saban Films release.

Running time: 1:41