The nicknames underscored the dread he inspired. The East Area Rapist. The Original Night Stalker. The Diamond Knot Killer. The Golden State Killer.

A brutal, homicidal spree terrorised California in the 1970s and 1980s and prompted one of America’s most intense manhunts.

He wore a mask and gloves, broke into homes and put a blade to victims’ throats before committing atrocities. “Shut up or I’ll kill you,” he said.

Authorities studied his modus operandi – the reconnaissance, the knots – and offered rewards for information. They distributed sketches of the slender young man with blond hair blamed for 12 murders and at least 45 rapes from 1976 to 1986.

Years turned to decades and he remained free, his identity unknown.

On Tuesday evening came a denouement. A police taskforce pounced on a balding 72-year-old man as he emerged from his home in Citrus Heights, an affluent suburb outside Sacramento. Joseph James DeAngelo Jr, a former police officer, seemed too astonished to try to flee.

“He was very surprised,” said the Sacramento county sheriff, Scott Jones.

So was everyone else when authorities confirmed the news at a press conference on Wednesday, revealing that a DNA breakthrough had turned a cold case very hot. “This was a true convergence of emerging technology and dogged determination,” said Jones.

Joseph James DeAngelo. Photograph: Sacramento county sheriff's office

DeAngelo is being held without bail on suspicion of murdering Brian and Kate Maggiore in 1978 and Charlene and Lyman Smith in 1980. He is on suicide watch.

He allegedly committed some of the rapes and killings while a police officer – possibly while on duty.

“This defendant has been able to live here in a nice suburb in Sacramento,” said the Orange county district attorney, Tony Rackauckas. “Our team is going to work hard to make sure he never gets out.”

Bruce Harrington, whose brother Keith Harrington and sister-in-law Patrice Harrington were among the killer’s victims, also addressed the press conference. “For the 51 ladies who were brutally raped: sleep better tonight. He isn’t coming through the window. He is now in jail and he is history.”

A cottage industry of books and documentaries have kept the Golden State Killer in the public eye.

The true-crime author Michelle McNamara detailed the crimes and investigation in her book I’ll Be Gone in the Dark. Her husband, Patton Oswalt, an actor and comedian, helped finish the book after McNamara died in 2016. It became a bestseller and reportedly is the basis of a planned HBO series.

“If they’ve really caught the #GoldenStateKiller I hope I get to visit him. Not to gloat or gawk – to ask him the questions that @TrueCrimeDiary wanted answered in her ‘Letter To An Old Man’” at the end of the book, Oswalt tweeted.

If they’ve really caught the #GoldenStateKiller I hope I get to visit him. Not to gloat or gawk — to ask him the questions that @TrueCrimeDiary wanted answered in her “Letter To An Old Man” at the end of #IllBeGoneInTheDark. pic.twitter.com/32EHSzBct5 — Patton Oswalt (@pattonoswalt) April 25, 2018

Jones told reporters the book helped keep the case in the public eye but did not prompt the breakthrough, dismaying some of McNamara’s fans on social media.

Anne Marie Schubert, Sacramento’s district attorney, said a taskforce assembled in 2016 pooled information and resources from the FBI and multiple police forces across California. “The answer was and always was going to be in the DNA.”

Authorities hailed laboratory experts and old-fashioned detective work but did not reveal how they matched the DNA to DeAngelo, only that the breakthrough came last week, after which they put him under surveillance.

His relatives were cooperating, said Scott, the sheriff. “It’s quite a shock to them, as you might expect.”

Neighbours expressed shock as police scoured DeAngelo’s beige bungalow and removed some property, including two cars, a boat and a motorcycle. They told reporters the only notable detail about him was his occasional loud swearing while doing DIY in his yard.

Authorities announce the arrest in Sacramento. Photograph: Fred Greaves/Reuters

DeAngelo served as a police officer with the Exeter and Auburn police departments before being fired in 1979 on suspicion of shoplifting a hammer and a can of dog repellant from a Citrus Heights store.

The East Area Rapist got his name by breaking into homes from 1976 and using laces to truss victims.

His fifth victim, Jane Carson-Sandler, wrote a book about the ordeal. “Shut up, shut up, shut up or I’ll kill you,” he said as he scraped a knife across her chest, drawing blood. “I just want your money.” That was a lie. He tied up her three-year-old son, then raped her.

The attacks grew more sadistic. He tied up husbands, placed cups and dishes on their backs and said they and their wives would be killed if the crockery slipped off.

By 1978, the attacks were murderous. The Maggiores were shot while walking their dog. The Smiths were bludgeoned to death. That year police found an essay believed to belong to him. “My 6th grade teacher gave me a lot of disappointments that made me very mad and made me built (sic) a state of hatred in my heart,” said one excerpt. Another page included an intricate sketch of a neighborhood and the word “punishment”.

The FBI set up a website in 2016 offering a $50,000 reward, saying by then the killer would be approximately 60 to 75 years old. “He may have an interest or training in military or law enforcement techniques, and he was proficient with firearms,” it said.

Carson-Sandler, the rape survivor, told the Island Packet newspaper the arrest had overwhelmed her with joy. “I’ve been crying, sobbing.”



