Those who've been working on the case say they found the "needle in the haystack" -- living in plain sight in the Sacramento County suburb of Citrus Heights where the 72-year-old was arrested overnight.
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"The magnitude of this case demanded that it be solved," said Sacramento County District Attorney Anne Marie Schubert.
Investigators say DeAngelo spread fear across the state from 1974 to 1986. He began his crime spree in and around Sacramento, moved on to the Bay Area and then to Southern California.
The crimes were meticulously planned. Investigators say DeAngelo wore a ski mask and broke into homes, then gagged, blindfolded and tied up his victims before carrying out his brutal attacks.
VIDEO: What we know about suspected 'Golden State Killer'
Who's Joseph James DeAngelo? What we know about suspected 'Golden State Killer'
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"For the 51 ladies who were brutally raped in this crime scene, sleep better tonight. He isn't coming through the window. He's now in jail, and he's history," said Bruce Harrington, whose brother and sister-in-law were among DeAngelo's murder victims.
DeAngelo only became a suspect days ago when investigators got a break in the case. Then a discarded DNA sample provided the confirmation they needed. DeAngelo was a former police officer who's worked near Visalia and in Auburn.
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"Very possibly he was committing the crimes during the time he was employed as a police officer. Obviously we will be looking into whether it was actually on the job," said Sacramento County Sheriff Scott Jones.
This case is far from over. DeAngelo has only been arrested for a few of the murders. Prosecutors promise more charges in the coming days.
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