As the killer was in their home, studying the map of the city while smoking a cigarette. It was already his second pack in a span of two hours. But it didn't bother him since he wasn't a mortal, oh no he was much worse then that. He was a vampire, but he didn't just feed in human blood. He also had powers those kind of powers that anybody among immortals was gifted with such as: blood bending, fire manipulation and manipulation of souls. He was also using his words as verbal warfare, he was a great manipulator to the point every of his victims basicly became nothing but a puppet on the strings he pulled, a mindless zombie following instructions they were given.
That's why many victims committed suicide or it was self inflicted harm because they were so brainwashed from the killer's manipulation.