CNN and selective color vision

http://simplyjews.blogspot.com/ A curios situation in the CNN reporting on the Austin TX serial bomber. Here is the passage that confused me mightily:

The first explosion killed 39-year-old Anthony Stephan House on March 2. The second blast on March 12 killed 17-year-old Draylen Mason. The third blast happened several hours later and critically injured a 75-year-old woman. Those three blasts all happened after someone left explosives-laden packages on the victims’ doorsteps. In the fourth blast, a device was triggered by a tripwire, injuring two white men, police said. The device was left on the side of a road in a predominantly white area.

So the first three blasts killed or injured three persons without any color attributed and the other blast injured two white persons.

Is there some special new kind of explosive material that could be set to injure a colorless person or a person of specific color, depending on the circumstances or on the bomber will?

Hmm… consider me confused. Like this:

P.S. I hope they will get the bastard. And there really is no need to research his color preferences. Just to shoot… http://simplyjews.blogspot.com/