I heard early in his career he took pictured of peoples eyes as they were dying...very serial killer-like fetish.
The guy named one of his devices the 'Thanatotron'. Derived from the Greek Thanatos, which means death.
Referencing your statement regarding picture taking, I believe that profilers would call the photos 'souvenirs'. Which is a hallmark of serial killers. They relive their crimes with them.
I will not be shedding any tears, that's for sure.