Through tears Thursday, she described her horror over how the suspect attacked her inside her "child's" bedroom covered with posters of things like rainbows and unicorns.
TIMELINE: A look back at the Golden State Killer's crime spree that lasted a decade
She said she overheard news of Joseph James DeAngelo's arrest yesterday and reached out to the director of the forensic lab who processed her case. He confirmed to her "this is it."
She said she is simultaneously relieved and tearful, saying "I couldn't be happier that it's over." She said friends and family who supported her through the ordeal in 1979 were en route to her current Bay Area residence to hug her and celebrate the arrest.
"Mary" says she will not go to court. She does not want to confront DeAngelo in person and has moved on with her life.
VIDEO: What we know about suspected 'Golden State Killer'
The "Golden State Killer" terrorized the bay area from the fall of 1978 to the summer of 1979. Back then he was known as the "East Area Rapist." He attacked 11 victims from Concord to San Jose -- eight of them in Contra Costa County.
Alameda County District Attorney Nancy O'Malley was a rape crisis counselor back then and worked directly with at least one of the victims.
She recalled the terror of women afraid to sleep with their windows open, fearful they were being stalked. She said, "I can't believe we caught him." She attributes his arrest to innovative new DNA processes along with "good old fashioned" police work.
She's fighting to get rape kits processed by police departments and labs in a more efficient manner to keep this kind of crime spree from ever happening again.
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