A suspected California serial killer who murdered at least 12 people and 45 rapes throughout the state in the 1970s and 80s is a former police officer, an official said.
A law enforcement official identified Joseph James DeAngelo, 72, who was fired from the Auburn Police Department in 1979, as the so-called Golden State Killer.
The official confirmed the name on condition of anonymity before an official news conference.
Armed with a gun, the masked attacker terrorised communities by breaking into homes while single women or couples slept. He sometimes tied up the man and piled dishes on his back, then raped the woman while threatening to kill them both if the dishes tumbled.
He often took souvenirs, notably coins and jewellery, from his victims, who ranged in age from 13 to 41.
DeAngelo was fired from the Auburn Police Department in 1979 after he was arrested for stealing a can of dog repellent and a hammer from a drug store, according to Auburn Journal articles from the time.
The FBI says it has a team gathering evidence at a Sacramento-area home linked to DeAngelo.
Sacramento County jail records show DeAngelo was arrested overnight on suspicion of two counts of murder.
Jane Carson-Sandler, who was sexually assaulted in California in 1976 by a man believed to be the so-called East Area Rapist, said a retired detective who worked on the case emailed her on Wednesday (US time) telling her they have identified the rapist and he's in custody.
"I have just been overjoyed, ecstatic. It's an emotional roller-coaster right now," Carson-Sandler, who now lives near Hilton Head, South Carolina, told the Associated Press.
"I feel like I'm in the middle of a dream and I'm going to wake up and it's not going to be true. It's just so nice to have closure and to know he's in jail."
Carson-Sandler was attacked in her home in Citrus Heights. A home in that community belonging to a former police officer was being searched on Wednesday by FBI investigators and police from several agencies.
Two neighbours who declined to give their names said authorities arrived before midnight. Sacramento County Jail records show the man who lives at the home was booked at 2.30am on suspicion of murder.
Sacramento County district attorney's spokeswoman Shelly Orio declined to comment before the news conference.
FBI and California officials in 2016 renewed their search for the attacker dubbed the East Area Rapist and announced a US$50,000 ($70,000) reward for his arrest and conviction. He's linked to more than 175 crimes between 1976 and 1986.
As he committed crimes across the state, authorities called him by different names. He was dubbed the East Area Rapist after his start in Northern California, the Original Night Stalker after a series of Southern California slayings, and the Diamond Knot Killer for using an elaborate binding method on two of his victims.
Most recently called the Golden State Killer, he has been linked through DNA and other evidence to scores of crimes.
Authorities decided to publicise the case again in 2016 in advance of the 40th anniversary of his first known assault in Sacramento County.
Neighbour Kevin Tapia, 36, said when he was a teenager, DeAngelo falsely accused him of throwing things over their shared fence, prompting a heated exchange between DeAngelo and Tapia's father.
He said DeAngelo could often be heard cursing in frustration in his backyard.
"No one thinks they live next door to a serial killer," Tapia said. "But at the same time I'm just like, he was a weird guy. He kept to himself. When you start to think about it, I could see him doing something like that but I would never suspect it."
"He was young - anywhere from 18 to 30 - Caucasian, and athletic, capable of eluding capture by jumping roofs and vaulting tall fences," crime writer Michelle McNamara wrote in a Los Angeles magazine profile of the old cases.
"To zero in on a victim he often entered the home when no one was there, learning the layout, studying family pictures and memorising names," she wrote. "He disabled porch lights and unlocked windows. He emptied bullets from guns. He hid shoelaces or rope under cushions to use as ligatures.
"These manoeuvres gave him a crucial advantage because when you woke from a deep sleep to the blinding flashlight and ski-masked presence, he was always a stranger to you, but you were not to him."
Police first dubbed the man the East Area Rapist, as he would not begin killing until much later in his spree.
The first known attack, Katie Mettler wrote in the Washington Post, took place in the middle of the night in the summer of 1976, when a man snuck into a home in east Sacramento County, raped a young woman and left.
He raped again a few weeks later, then again and again, dozens of times. After a year, two dozen women had been attacked and a sheriff's department spokesman told the Associated Press that some residents had started "sleeping in shifts", because the man would strike even if others were home.
His 44th victim was a 13-year-old girl in the Walnut Creek area in 1979, the Mercury News reported. He allegedly raped her at knifepoint while her father and sister slept down the hall, told her he'd kill her if she told anyone, and fled through the back yard, past her playhouse.
Police rebranded him the Original Night Stalker after he began to kill in 1978, Mettler wrote. He found a married couple walking their dog in the Sacramento Area, chased them and shot them to death.
Future killings would be much more meticulous, and spread from Sacramento to southern California.
On December 30, 1979, police in Goleta found a husband and wife dead in their house - one shot through the heart and one in the back of the head.
"As detectives processed the crime scene, they stepped around a turkey carcass wrapped in cellophane that had been discarded on the patio," McNamara wrote in Los Angeles Magazine. "The killer had opened the refrigerator and helped himself to [victim Robert] Offerman's leftover Christmas dinner."
Another couple were murdered in Ventura three months later, she wrote. Then yet another couple, in a gate community in Dana Point.
He left few clues, and only betrayed a few patterns as his violence escalated: he often ate from his victims' fridges; often took tokens from their personal belongings, like class rings.
He usually tied up the men before he killed them and almost always raped the women.
Police did not realise the East Area Rapist and Original Night Stalker were the same person until DNA tests linked the crimes in the early 2000s, McNamara wrote.
By then, his spree was long over - the last victim was 18-year-old Janelle Cruz, bludgeoned to death in Irvine in 1986 - and the trail had gone cold.
Notorious serial killers in the US
Darren Deon Vann was arrested in the killing of a 19-year-old woman at a motel in Indiana and later confessed to the murders of six other women. He is awaiting trial.
2007-2009: Anthony Sowell was convicted of killing 11 women and hiding the remains in and around his home in Cleveland, Ohio. He is on death row in Ohio.
2005-2006: Mark Goudeau, a former construction worker who was also known as the "Baseline Killer", was convicted of killing eight women and a man in Phoenix, Arizona. He was sentenced to death in 2011 and remains on death row in Arizona.
2002: Lee Boyd Malvo and John Allen Muhammad randomly killed 10 people in Washington, D.C., Virginia and Maryland as they pumped petrol and went about their business during a three-week period in 2002. Malvo is serving several life sentences at a Virginia prison; Muhammad was executed in Virginia in 2009.
1997-1999: Angel Maturino Resendiz was convicted of murdering a Houston woman, but was linked by confessions and evidence to at least 12 other killings nationwide. He's on death row in Texas.
1996-1998: Robert L. Yates jnr was convicted of two murders but admitted to 15. He's on death row in Washington state.
1990-1993: Heriberto Seda, aka "the Zodiac Killer", killed three people and wounded four in New York City and is serving a 235-year sentence.
1989-1990: Aileen Wuornos, a rare female serial killer, was convicted of murdering six men while working as a prostitute along highways in central Florida. She was executed in 2002.
1985-2007: Lonnie Franklin, known as the "Grim Sleeper", was convicted in the deaths of nine women and a teenage girl in Los Angeles. Franklin was linked at trial to 14 slayings, including four women he wasn't charged with killing. Police have said he may have had as many as 25 victims. He is on death row in California.
1984-1985: Charles Ng and Leonard Lake were convicted of murdering 11 people. Ng is on death row in California; Lake committed suicide.
1984-1985: Richard Ramirez was convicted of killing 14 people during break-ins in the Los Angeles area. He is on California's death row.
1983: Henry Lee Lucas told police he had have killed as many as 600 people. He later recanted. Lucas had 13 murder convictions and was sentenced to at least 10 life terms, then was sentenced to death in Texas for the murder of a hitchhiker known as "Orange Socks". Then-Govenor George W. Bush commuted that to life in prison, his only commutation as governor. Lucas died in prison in March 2001.
1979-1981: Wayne B. Williams of Atlanta was sentenced to two life terms for killing two boys, but police believed he may have been responsible for up to 28 deaths.
1978-1995: Theodore Kaczynski, aka "the Unabomber", carried out a series of mail bombings that killed three people and injured 23. He is serving a life sentence at a federal prison in Colorado.
1978-1992: Jeffrey Dahmer was sentenced to 16 consecutive life terms for killing 17 men and boys, most in Milwaukee. He was killed in prison in 1994.
1977-1978: Ted Bundy was convicted of three Florida slayings, including that of a 12-year-old girl. He confessed to more than 30 and was executed in 1989.
1977-1978: Angelo Buono jnr was convicted of murdering nine young California women and sentenced to life in prison without parole. Kenneth A. Bianchi pleaded guilty to five of the murders, agreeing to testify against his cousin in return for being spared a possible death sentence. He was sentenced to five concurrent life terms in prison.
1976-1986: Joseph James DeAngelo, a former police officer in Auburn, California, is suspected of being the so-called Golden State Killer. He has been booked on two murder charges but is suspected of 170 crimes, including a dozen murders and 45 rapes between 1976 and 1986.
1976-1977: David Berkowitz, aka "Son of Sam", killed six people and wounded seven others in New York City. He is serving six consecutive 25-years-to-life sentences.
1974-1991: Dennis Rader, who called himself BTK for "bind, torture and kill", murdered 10 people in Wichita, Kansas. He was arrested in 2005 and is serving 10 consecutive life sentences at a Kansas prison.
1972-1978: John Wayne Gacy of suburban Chicago killed 33 young men and boys. He was executed in 1994.
February-May 1971: Juan Corona was convicted of murdering 25 farm workers whose bodies were found buried near Yuba City in northern California. He is serving a life sentence.
- AP - additional reporting Washington Post