After nearly forty years, an arrest has been made in the case of the Golden State Killer, the serial killer and rapist who was active in California in the 1970s and 80s, just months after a popular book was published about the case.

Sacramento police arrested Joseph James DeAngelo, 72, early on Wednesday morning and booked him on two counts of murder.

The Golden State Killer – who was also known as the East Area Rapist and the Original Night Stalker – has been the subject of fascination and fear for decades. He is believed to have killed at least 12 people, raped at least 45 people and robbed more than 120 homes across the state of California between 1976 and 1986. His alleged crimes are noted for the calculated brutality and extreme level of planning.

The crimes have received a more intense spotlight over the past few months thanks to a new book published in February. I’ll Be Gone in the Dark was written by Michelle McNamara, who died in April 2016. Her husband – comedian Patton Oswalt – commissioned a journalist and researcher to complete McNamara’s book, based on her notes.

“The magnitude of this case demanded that it be solved,” Sacramento County District Attorney Anne Marie Schubert said at a news conference. “We found the needle in the haystack, and it was right here in Sacramento.”

Across the long investigation of the case, it was believed that the suspect likely had military or law enforcement training. This lines up with DeAngelo – the district attorney has confirmed he was an ex-cop whose service overlapped with the period of some of the murders.

Police sketches of the GSK. Photo: FBI.

You can watch the entire press conference below – the action doesn’t really begin until about 14:11:

Oddly, a local angle to the Golden State Killer case sprang up earlier this week. The Australian reported that US authorities investigated a theory that the killer had left California and came to Victoria, based on similarities with the infamous Mr Cruel case. Victoria Police ruled out the link.

This’ll be the start of a long prosecution process, but for the victims’ families and so many people fascinated by the case, it’s a huge moment.