Samuel Little is a perfect example of some one category 3, that was eventually caught...
He was charged with 4 counts of murder in 2013, but in 2018 he was connected to a murder in Texas. Further investigations connected him to over 50 murders over almost 40 years, but he claims 93. The police hadn't connected ANY of the murders until he was picked up on narcotics charges and his DNA matched a bunch of cases in LA. He'd been in and out of jail 26 times between '61 and '75 for lessor charges, and was even charged with murder in '82, but was acquitted.
It was Category 3 enough that they never connected all the murders together until he told them... We didn't know he was a serial killer, and we didn't know that there WAS a serial killer running around.
He was charged with 4 counts of murder in 2013, but in 2018 he was connected to a murder in Texas. Further investigations connected him to over 50 murders over almost 40 years, but he claims 93. The police hadn't connected ANY of the murders until he was picked up on narcotics charges and his DNA matched a bunch of cases in LA. He'd been in and out of jail 26 times between '61 and '75 for lessor charges, and was even charged with murder in '82, but was acquitted.
https://en.wikipedia.org/wiki/Samuel_Little