Oxygen’s Golden State Killer: Main Suspect sounds like a true-crime smash hit. There’s the setting, rife with sleepy California small towns where something bad is bound to happen; the concerned neighbors and colleagues of the suspect who, though they can’t put their finger on it exactly, think something’s just off about the guy; and, of course, vicious crimes that escalate from petty burglaries to rape and, eventually, murder. Stephanie Gosk, an investigative journalist from NBC, hosts the documentary and retraces the murderer’s steps throughout his decade-long crime spree across central and southern California.

Michelle McNamara, a writer and crime blogger from Los Angeles who was married to comedian Patton Oswalt, is frequently credited for the resurgence of public interest in the Golden State Killer. McNamara’s book I’ll Be Gone In The Dark, published two years after her untimely death in 2016, details the horrifying decade-long crime spree. She coined the all-encompassing nickname for the killer, who was previously known by other monikers specific to the regions of his crimes.

Following the precedent set by McNamara, Golden State Killer takes an engaging, in-depth look at DeAngelo’s criminal past, compiling interviews with former colleagues, neighbors, and survivors to piece together a chilling portrait of a criminal who’d often taunt his victims and didn’t hesitate to kill if necessary.

The alleged identity of the Golden State Killer is revealed early on: 72-year-old Joseph DeAngelo, a veteran of the armed forces and former police officer. Recently arrested and identified through DNA after years of investigators combing through evidence, DeAngelo stands accused of 12 counts of murder, but has yet to be named in the more than 50 rapes also attributed to the Golden State Killer. DeAngelo appears at his arraignment looking frail and confused; photos of him from recent years suggest a kindly, if addled, grandfather—not the vicious criminal who murdered a dozen people and raped scores of women.

DeAngelo’s criminal behavior allegedly began in 1974, in the small, northern California town of Visalia. Many familiar with the Golden State killer’s later crimes believe that it all started here, with the burglar known as the “Visalia Ransacker.” The ransacker would carefully break into homes while the inhabitants were away, and wouldn’t take much of value, preferring instead to rifle through women’s undergarments and steal only personal items, like a single earring or pair of cufflinks. But these disturbing break-ins were only the beginning, as the ransacker would quickly transform into the East Area Rapist.

Responsible for dozens of rapes, the suspect would frequently taunt his victims before and after the attack. When targeting couples, he’d tie them both up, then rape the woman in a separate room, forcing her male companion to listen to her screams. The East Area Rapist often lingered for hours, raiding the victims’ fridge for snacks in between raping his female victims. He’d stack plates on the backs of bound male victims, and told them he’d kill everyone in the house if he heard them rattle.

Golden State Killer seamlessly transitions from the crimes of the Visalia Ransacker and the East Area Rapist into the dozen murders that marked the end of the killer’s crime spree. Specifically targeting couples, the Golden State Killer observed his victims for days before breaking in. He’d force the woman to tie up her male companion, then bludgeon them both to death. This continued for several years until the crimes abruptly stopped in 1986, as suddenly as they’d begun some twelve years earlier.

The documentary highlights how unassuming DeAngelo appeared to those who knew him. The crimes of the Golden State Killer, AKA the Visalia Ransacker or East Area Rapist, seem out of character, acquaintances say; by many accounts, he was a charming old man who wouldn’t hurt a fly. But an employee from a diner DeAngelo frequented as an older man provides a chilling anecdote: DeAngelo gifted her a belt one time after noticing her pants were too loose. Already creepy, the encounter took a decidedly macabre tone when a smiling DeAngelo told the waitress, “You can wear it around your waist, or around your neck.”

“ The crimes of the Golden State Killer seem out of character, acquaintances say; by many accounts, he was a charming old man who wouldn’t hurt a fly. ”

Golden State Killer excels when it includes these eerie witness anecdotes; former neighbors of DeAngelo recall him keeping odd hours, and his extreme anger when something as small as a soda spilled. Several families who lived next to DeAngelo at different points in his life even accuse him of poisoning their dogs—DeAngelo made no secret of his hatred for the animals. The documentary is strongest in these sensationalist moments; they don’t necessarily add much to the narrative, but they do offer lurid glimpses into the life of a killer who, by many accounts, led a double life.

What Golden State Killer lacks, however, is momentum. Most successful true-crime documentaries (notable exceptions being Netflix’s Wild Wild Country and Making A Murderer) revolve around one question: who did it? The filmmakers’ quest to discover the perpetrator of the heinous crime in question (or, if there’s already a suspect, to explore the probability that they committed said crime) gives the documentary a clear objective. But with the identity of the suspected killer revealed in the first few minutes of the documentary, there’s little left to guide Golden State Killer except for a vague curiosity—why did DeAngelo allegedly kill and rape so many people? We simply don’t know.

In the already oversaturated genre of true-crime documentaries, Golden State Killer doesn’t break new ground; it’s a story of a disturbed, violent individual we’ve heard before and will undoubtedly hear again. While the film is by no means unwelcome, it is a bit underwhelming—in a genre that’s become known for being anything but.