Rufus Norris’ adaptation of the West End musical London Road (B) is a curious case of hybrid musical documentary. This syncopation of vérité verse attends the tale of the plainspoken citizens of Ipswich, England, changed forever in 2006 by a quintet of killings of prostitutes who had emerged as curbside phantoms on the scene of a benignly neglected, sleepy borough. Actresses Olivia Colman and Anita Dobson lead an ensemble of sturdy players who brilliantly sing-speak the actual lines of a forensic investigation and subsequent media coverage of the aftermath of the murders, bringing humanity to the random viciousness befalling domestic tranquility. Even Tom Hardy, the most internationally recognized star in the film, has a nice singing bit as a roguish taxi driver tossing out conspiracy theories. Through the vocals of the victimized women living on the margins of town, we learn a little about the irony of a neighborhood watch wary for certain infractions and blind to a city’s most aching needs. Despite the chilling subject matter, there’s an overriding spirit of nihilistic dark comic glee that the filmmakers are having such a good time reinventing how a musical can take shape. Although recorded live, the dulcet dialogue has a delightful dubsmash quality with “ums” and “you knows” treated like they’re the angelic utterances of Jackie Evancho. The asymmetrical, casual quality of the music recalls Dancer in the Dark or Dr. Horrible’s Sing-Along Blog and makes this essential viewing for fanatics of the musical form in its perpetual evolution or of droll, defiant British storytelling. The narrative sometimes yearns to break forth a bit more from its mumblecore melodies and doesn’t really ever make that leap. It would have been interesting to see how an Alan Parker or Ken Russell would have dabbled with more forceful visual panache into this subject matter. As it stands, Norris has challenges honing in on the exact plum protagonists most worthy of our attention. And the procedural story isn’t quite shocking or special enough to warrant this passionate a cinematic treatment. Still, this unconventional yarn is a thrilling detour from traditional storytelling.