Scott Capurro is not a comic known for shying away from controversy ­ in fact, he'd be lost without it. So it's no surprise that his latest play touches more than a few raw nerves.

Loaded is a hymn to the killer; the brooding evil Capurro professes to find such a turn-on. "Ian Huntley ­ the only hot man from grimy Grimsby," he muses, lost in fantasy, drooling that the Soham child-murderer is "dreamy".

However, it wasn't Huntley who captured Capurro's heart, but Erik Menendez, one of two wealthy teenagers who killed their mother and their abusive, tyrannical father at their Beverly Hills mansion in 1989.

Driven by admiration and curiosity, the San Franciscan comic became so obsessed with the teenager that he wrote to him in his prison cell while awaiting trial. Menendez wrote back, with a bizarrely frank and familiar tone, starting a two-way correspondence that forms the backbone of this dark piece.

What isn't obvious, however, is whether Capurro's lust is genuine, or whether, like some unhinged Henry Root character, he wrote in some misplaced mischief or morbid curiosity, simply to provoke a response. Either way, his eroticism of the gruesome provides some uncomfortable laughs at this morally suspect material.

The play contrasts the comic's pen-pal relationship with America's highest-profile murder suspect to everyday contact he had with colleagues at the car dealership he was working at, pondering whether he should tell the emotionally void accountant Simon his secret ­ and whether he should pounce on him sexually.

These scenes are less purposeful and less interesting, devoid of the inherent curiosity that letters from a killer will always hold, exposing a substantial lack of insight at the heart of the piece. Capurro muses that his connection to Erik is somehow linked to the strained relationship he has with his own, distant father ­ who is nothing like the monster Menendez Snr so obviously was ­ but only to top and tail the piece, not as an inherent thread.

What Loaded lacks in insight, though, it makes up for in grippingly imaginative storytelling, evil barbed wit and impressive performances ­ both from the arch Capurro and from the versatile James Holmes, who plays all the supporting characters. It's this skilful execution of an interesting, if flawed, script that makes the play so watchable, even if it proves surprisingly slight on substance.