B.K.-Blood Killer (refering to the gang)
B.K.A.-Blood Killer Always (again the gang) B.K. and B.K.A. are abreviations for the Bloods. Just like Crips have Community Revolution In Progress. Often B.K. and B.K.A. can be found in grafitti all over the world. There are even documented cases of it in parts of Asia.
In the middle of the night I tagged "B.K.A." to show my pride