Golden State Killer suspect caught and identified as former police officer Joseph James DeAngelo

A former police officer has been arrested in connection to a long-unsolved string of rapes and murders which are believed to have been carried out by the "Golden State Killer".

Joseph James DeAngelo was picked up by authorities in California, who allege he was behind 12 murders and at least 50 rapes in the 1970s and 1980s, along with a number of burglaries. He was also known as the "East Area Rapist".

Sacramento County Sheriff Scott Jones said the 72-year-old was identified with a DNA test.

“For over 40 years”, Sacramento County district attorney Anne Marie Schubert told a press conference, “countless victims have waited for justice”.

Sheriff Jones added that an investigative team formed two years ago was given “virtually unlimited resources and freedom” to catch the killer.

Mr DeAngelo now faces murder charges across multiple counties for decades-old killings.

As the string of crimes were making headlines, Mr DeAngelo was working as a police officer. He worked for two different police departments from 1973 to 1979, Mr Jones said.

“Very possibly he was committing the crimes during the time he was employed as a police officer”, Mr Jones said, and authorities were investigating whether Mr DeAngelo committed any crimes while on duty.

As the list of victims and geographical area in which they were targeted expanded, with cases in at least 10 different counties, the suspect earned more additional nicknames.

“He’s been called the East Side Rapist. He’s been called the Visalia Ransacker, the Original Night Stalker and the Golden State Killer”, Orange County district attorney Tony Rackauckas said. “Today, it’s our pleasure to call him ‘defendant’”.

The lack of arrests haunted California law enforcement for decades and was a “source of great frustration”, Ventura County district attorney Gregory Totten said.

For people growing up in Sacramento, where the first cluster of crimes occurred, “the memories are very vivid”, Ms Schubert said.

She added: “For many of us [in law enforcement], it was more than a professional commitment. It became personal”.

Footage from the Sacramento suburb of Citrus Heights showed dozens of law enforcement officials, many of them with the FBI, outside a home surrounded by yellow tape.

One of the alleged rapist’s victims told the Island Packet newspaper that she was “overwhelmed with joy” after detectives contacted her this week to inform her of the arrest.

“I've been crying, sobbing”, Jane Carson-Sandler said.

Authorities had redoubled their efforts to catch the suspect in recent months, with the Sacramento County District Attorney's Office last year releasing a list of items believed to have been stolen by the killer in the hopes someone would recognise them.

“We are in the hunt for a serial killer here in California”, Ms Schubert said at the time.

While the Australian reported that authorities in California and Australia had spoken to explore links between the East Area Rapist and “Mr Cruel”, who is suspected of committing a series of violent attacks in Australia in the 1980s, Ms Schubert said there was no evidence of a connection.

“We have no information” linking the suspect to Australia, she said.