Thank you Antonio...good point! I also don't want to give the impression that there is a classic signature for those who kill others...although it would be easy for a researcher to take the charts of a significant number of "serial" killers and tally up what they do have in their Bazi charts in order to determine whether or not a correlation exists.
However, it is pretty clear that when one reads some of the ancient BaZi texts, as both Joey Yap and Jerry King have done, and then go on to present some of their principles--such as "excess" Eating Gods turning into a "negative" Hurting Officer, or excess Direct Officers turning into negative Seven Killings--that those who do go on a shooting spree like this young man did, that there is likely a strong positive correlation between descriptors. In other words, it is pretty easy to understand some of the descriptors of what comprises a negative Hurting Officer, a negative Seven Killings, and a negative Rob Wealth. And it would appear that many killers display these negative characteristics...
But it is also important to mention that an excess of Eating Gods, Friends, or Direct Officers does not automatically mean that they will definitely turn into a negative Hurting Officer, a negative Rob Wealth, or a negative Seven Killings. However, the potential does exist, as stated in the Bazi classics. And even if they do turn "negative", it does not automatically mean that that person will sooner or later go on a shooting spree...
This is why it is so important, even essential, to look at their charts not only through the lens of the Four Pillars of Destiny, but also through the lens of western astrology, Jyotisha, numerology, palmistry, face reading, etc.