Our age’s chief exemplar of evil’s banality might be Jeffrey Dahmer, the unassuming chocolate factory worker who in 1991 was found to have murdered, experimented on, dismembered, and eaten 17 victims in his Milwaukee apartment. Writer/director/editor Chris James Thompson’s documentary The Jeffrey Dahmer Files revisits the gruesome tale via the perspective of the investigation’s medical examiner and lead detective, as well as Dahmer’s neighbor, all of whom recount their experiences with horror (neighbor), disbelief (medical examiner), and borderline-creepy pride (detective). Alas, new insights are sorely lacking from their various anecdotes, as well as from the archival footage and dramatic re-creations of Dahmer’s day-to-day errands—eating fast food on the bus, buying the blue barrel in which he preserved skeletons—that further highlight the psychopath’s outward mundanity. Thompson assembles his footage with an expert’s touch, but what his film lacks is its own perspective on these atrocities. Other than making plain that Dahmer was a deranged loner on a twisted search for companionship (hence his attempt to drill holes in his victims’ heads to transform them into docile zombie lovers), Thompson reveals little that couldn’t be gleaned from the books, articles, and true-crime TV shows on this killer.