The Hillside Stranglers case was notorious and unusual in that it was a pair of serial killers and for a while they were killing so prolifically. Typically serial killers “work” alone and pause quite a bit between killings. I think these days they’d have been caught a lot earlier, because if I remember correctly at least one of the suspects had a criminal record and would’ve had DNA on file as well. Bianchi’s brazen attempt to manipulate psychologists was also notorious, though not unprecedented. The Son of Sam killer (who might have largely made up or exaggerated his record, however) also did the same. The truth is that insanity defense works less than 1% of the time. I personally don’t think multiple personality disorder truly exists-it’s just made up by the “patient” to escape responsibility (though usually not serial killings!). It’s sort of the wannabe actor’s “mental illness.”
Multiple personality disorder does exist, but it's extremely rare. It IS a form of avoidance even though they may not consciously wanting to evade their responsibilities. This kind of "ability" of summoning another personality to come out to take care the situation (or fulfill certain desire) was developed when a person was still a child. A child would fantasize another person appears magically to handle a difficult, or perhaps even traumatic, situation for them. That's how multiple personality disorder started to develop, as far as I know. Of course in the given case, it's fake and it's one way to try to escape responsibility.
