I am currently in the middle of reading the book on my Kindle “I’ll Be Gone in the Dark” by Michelle McNamara which tells the story about, what is, or better was, considered a cold case. The book tells the gripping story about a mysterious and violent predator, later nicknamed the “Golden State Killer”, who committed fifty sexual assaults in Northern California before moving south, where he perpetrated ten sadistic murders (see https://www.amazon.com/dp/B0792LVP7T). 

Thanks to the possibilities which DNA later offered, in combination with similarities of different M.O.’s the investigators learned about, it became possible to link multiple cases to the same perpetrator. In 2018 they nabbed a suspect,