True crime writer Michelle McNamara’s writing and passion helped catch ex-cop responsible for 12 murders, at least 50 rapes, home invasions and burglaries.

The arrest of a retired 72-year-old cop, the Golden State Killer, is all down to Michelle McNamara, a crime-writer who worked tirelessly researching the case before passing away suddenly in 2016.

Her widower, the comedian and actor, Patton Oswalt tweeted “You did it!” shortly after Joseph James DeAngelo, who is suspected of carrying out 12 murders and at least 50 rapes was arrested at his California home.

The assailant, who until this point had been unknown, caused terror in the Sacramento and Los Angeles during the 1970s and ‘80s. Known as the Golden State Killer, East Area Rapist, and the Original Nightstalker, it is believed that DeAngelo could be the man behind 12 murders, at least 50 rapes, home invasions and burglaries.

DeAngelo has been charged on two counts of murder so far. He was connected to the crime spree by DNA testing. Sadly, the person who played a vital role in building the case is not here to see the result.

McNamara, a true crime writer, died of an undiagnosed heart condition in 2016. She was just 46 and left behind her husband Patton Oswalt and their young daughter.

McNamara's book, “I'll Be Gone in the Dark: One Woman's Obsessive Search for the Golden State Killer” was published in February.

Goodnight, Michelle. You did good. You aimed a light and helped the hunters catch a monster. (Photo credit @vonswank) #MichelleMcNamara #IllBeGoneInTheDark #GoldenStateKiller pic.twitter.com/NYrc7dN16k

— Patton Oswalt (@pattonoswalt) April 26, 2018

The late author studied the crime spree in detail. She met with victims, poured over reports and even recruited retired homicide detectives to help. It was McNamara who coined the nickname the Golden State Killer.

Although local law enforcement have not credited McNamara with involvement they described the case as “a source of great frustration” and said McNamara and her blog posts on the case, on True Crime Diary, “kept interest and tips coming in but other than that there was no information extracted from that book that directly led to the apprehension.”

Also, the cops will NEVER and HAVE NEVER credited a writer or journalist for helping them solve a case. But every time they said #GoldenStateKiller they credited the work of #MichelleMcNamara and #IllBeGoneInTheDark.

— Patton Oswalt (@pattonoswalt) April 25, 2018

McNamara’s widower said his wife would have had no interest in praise or credit but tweeted “She cared about the Golden State Killer being behind bars and the victims getting some relief.”

Those who were murdered were:

Brian Maggiore, 22, Rancho Cordova, 1978

Katie Maggiore, 20, Rancho Cordova, 1978

Dr Robert Offerman, 44, Goleta, 1979

Dr Debra Alexandra Manning, 35, Goleta, 1979

Charlene Smith, 33, Ventura County, 1980

Lyman Smith, 43, Ventura County, 1980

Keith Eli Harrington, 24, Dana Point, 1980

Patrice Bricoe Harrington, 27, Dana Point, 1980

Manuela Witthuhn, 28, Irvine, 1981

Cheri Domingo, 35, Goleta, 1981

Gregory Sanchez, 27, Goleta, 1981

Here Patton Oswalt talks about his wife’s work and the Golden State Killer on Seth Meyer’s show on Wednesday night:

McNamara revealed her obsession with the Golden State Killer’s case back in 2013, in an article for Los Angeles Magazine. It was this article that prompted HarperCollins to offer her a book deal.

In 2011 on her blog McNamara wrote "I'm drawn to cases that aren't so high profile, that are maybe even a little neglected, but which have enough evidence and clues that anyone with a will and an internet connection can try to piece together the puzzle. That's exciting to me."

The Independent reports that McNamara’s obsession became to take a toll on her health and she suffered from anxiety and insomnia. She turned to medications - Xanax, Adderall and Fentanyl – for some relief but it is believed that the drugs could have played a role in her death. She died in her sleep on April 21, 2016.

HBO is currently producing a documentary on the Golden State Killer.

On social media tributes have poured in for McNamara and her work:

Three cheers for #MichelleMcNamara! Good things can happen! https://t.co/tZsZ0XUAua

— Kumail Nanjiani (@kumailn) April 25, 2018

I HAVE NO WORDS except those of #michellemcnamara #GoldenStateKiller pic.twitter.com/xKFgncHRpQ

— christina c (@chriscat19) April 25, 2018

Can’t find what time press conference on the Golden State Killer will be. All other plans for today swiftly tossed out the window. #MichelleMcNamara

— Heather Whaley (@HeatherWhaley) April 25, 2018

This #GoldenStateKiller thing is fascinating. It's like #MichelleMcNamara reached out from beyond, grabbed the killer by the collar and said, "Nope. You aren't going anywhere, asshole."

— Brian Lambert (@stink_dumb) April 25, 2018

#MichelleMcNamara you are a true hero. I hope you are looking down and smiling. #IllBeGoneInTheDark .

— Marah Mason (@MarahMason) April 25, 2018

Take a bow, #MichelleMcNamara. You earned it, girl. https://t.co/FSB3n3PJOK

— shauna (@goldengateblond) April 25, 2018

Joseph James DeAngelo, believed to be the Golden State Killer.