In December 2004, in the midst of final exams, four young men robbed the rare-book room at the library of Transylvania University in Lexington, Ky. A Vanity Fair article a few years later described the heist as one part “Ocean’s 11,” one part “Harold & Kumar,” which might raise your hopes for “American Animals,” a new movie that reconstructs the crime.

But the film, written and directed by Bart Layton, can’t quite decide what it wants to be: a slick, speedy caper; a goofball comedy; or a commentary on the state of the American soul.

It’s none of those — a tame and toothless creature that is neither fish nor fowl.

Dispensing with the usual vague “based on a true story” smoke screen, “American Animals” claims to show the truth about what happened. The actual perpetrators show up as narrators, offering slightly different but essentially compatible versions of events with at least the partial wisdom of hindsight. Their presence adds a patina of documentary credibility. Their younger, more irresponsible selves are played by professional actors, who re-enact the hectic planning, frenzied execution and inevitable unraveling of the theft.

The biggest prize is an exquisite first edition of John James Audubon’s “The Birds of America,” which catches the eye of Spencer Reinhard (Barry Keoghan), an art student at Transylvania. He proposes stealing it, perhaps as a joke, to his friend Warren Lipka (Evan Peters), a University of Kentucky student with an impulsive, volatile temperament. The two are an interesting study in contrasts. Spencer is moody, cerebral and prone to bouts of caution and common sense. Warren, whose parents are divorcing and who is in danger of losing his athletic scholarship, is wilder, perhaps even to the point of instability.

The two of them nudge each other across the line that separates fantasy from felony. “What if?” gives way to “How,” and before long Warren is flying to Amsterdam to meet with potential buyers for the loot, and Spencer is sketching floor plans and escape routes. They enlist two more accomplices: Eric Borsuk (Jared Abrahamson), a tightly wound accounting student, and Chas Allen II (Blake Jenner), a brash young entrepreneur. The only person standing in their way is Betty Jean Gooch (Ann Dowd), the librarian who controls access to the special collections.

The motives of the young men are something of a puzzle, as are those of the filmmakers. “American Animals” sometimes revels in their rebellious spirit and sometimes mocks their shallowness and lack of discipline. Though the thieves are dazzled by the prospect of easy money, they seem driven less by greed than by a vague grudge against the universe. Warren in particular sees the heist as an act of existential revolt against conformity, a chance to break out of the dreary destiny that seems to be the lot of young men oblivious to their own privileges.

Interviews with their parents and glimpses of their noncriminal pursuits emphasize that these are nice kids. What that seems to mean, mostly, is that they are white and middle class, entitled to the benefit of every doubt even when they are showing their cruel, selfish or stupid sides. The movie doesn’t romanticize or judge them, but it also shies away from the kind of objective naturalism that would challenge viewers to think about what this story might mean. The action is carried along on jumpy, poppy editing rhythms and on-the-nose song cues. (“New York Groove,” for example, when the scene shifts briefly to New York.)

Director Bart Layton, making his fictional feature debut, is blessedly more competent than his characters, but there is something soulless and mechanical about “American Animals,” as if it had been made by a Martin Scorsese smartphone app and scored to a Spotify classic rock playlist. Like the robbery itself, it must have seemed like a good idea — a lark, a warning, a statement — at some point.