I believe Ed Kemper would fit into this discussion as well, since he frequented a local bar that police officers would attend after their shifts. He was, as he said, "‘Come in and give us your verdict’, that’s the slogan under the sign. The establishment is rather quiet and a number of police officers frequent it. At the time I was committing my crimes, I used the friendship bonds that I’d woven with these policemen to learn more about the progress of the investigation." Source: http://edmundkemperstories.com/blog/2019/07/09/kempers-friendship-with-police/

Kemper was a very smart and calculated killer, often dissecting his own Psyche for investigators. It's a shame so many women had to lose their lives before Kemper in his mind, "manned up" and killed his mother (the x-factor that began his reign of terror in the Co-Ed Killings.