The central image of Coyote on a Fence, Bruce Graham’s literate and moving play about the equivocal morality of sentencing a human being to die, is invoked by Bobby Reyburn, an inmate on death row, in a story he tells of a frightening childhood encounter. After becoming the target of a gang rape, he was running to his uncle’s house for shelter when he came upon a monster. It turned out to be a dead coyote that had been preying on the neighborhood and had been shot and stuck up on a fence. As his uncle explained to the terrified boy, " The animal is a predator and deserved to be killed " — the rationale expressed by those who believe in the death penalty, as well as a metaphor for Reyburn’s subsequent life and execution.

The play is set in a prison where two inmates from separate worlds are placed in adjoining cells: John Brennan, an educated man who killed a drug dealer in a moment of passion, and Bobby Reyburn, a semi-literate good ol’ boy who spouts the philosophy of the Aryan Nation. An abandoned child, Reyburn was probably legally insane when he set fire to an African-American church where 37 people died. Both men have been sentenced to death, but Graham tempers the evidence by looking at what drove them to their deeds.

The plot turns on Brennan’s efforts to confront the penal system by publishing a newspaper, the Death Row Advocate, and fomenting appeal after appeal. His case has caught the eye of a journalist from the New York Times, Sam Fried, a preppy liberal with biases of his own. The fourth character is Shawna DuChamps, a foul-mouthed, tough-talking prison guard who narrates the action straight to us as if we were reporters probing for the story. The play unfolds over a period of time but runs an hour and 40 minutes, with no intermission.

Although there are the usual clichés regarding Reyburn as a dropout whom society has failed and Brennan as the killer of a scumbag who might have deserved his fate, Graham draws his characters carefully, making them sympathetic without a sentimental cover. Under the direction of Nancy Curran Willis, who paces the show quickly, the quartet of actors deliver performances that illuminate their characters’ decisions without diminishing the heinous nature of their crimes.

Barlow Adamson as Reyburn is the ensemble standout, fashioning a multi-layered, memorable portrait of an American fascist, a hater who wants to take the country back for his own kind, as he puts it. His only regret, Bobby declares, is that he didn’t kill Jews rather than " niggers, " as he calls his victims. Fred Robbins’s older Brennan has a temper that he can’t control, and he dislikes Reyburn at first meeting, telling the friendly convict, " Don’t call me brother. " But these are two lonely men desperate for human connection, so gradually a relationship is forged.

Peter Papadopoulos’s Fried befriends Brennan but then betrays him in writing his story, all the while showing little emotion. Bobbie Steinbach is aptly mercurial as the straight-talking Shawna DuChamps, who controls her prisoners better than she does her conscience. Ruth Neeman’s spare but chilling set encompasses the compact world of the prisoners: a dog-run-like exercise lot stage right and the visitors’ room stage left, with the two cells at center stage. Peter Boynton’s sound environment of constant, grating noise helps to suggest the dehumanizing conditions of prison, where privacy is considered a danger to authority.

If the play falters in its too abrupt ending, it nonetheless delivers a balanced examination of the question whether one human being has the right to take the life of another. Yet I wonder about the playwright’s opinion. Unlike The Exonerated, the recently-in-Boston agitprop work from Jessica Blank and Erik Jensen that tells the true-life stories of people on death row who were innocent, Graham presents those who are guilty but makes a case for a closer look at the motivations behind their crimes.