I have spent so much time with criminals that they are starting to rub off on me... I can be easily bribed.
To gain the trust of a criminal informant I committed an illegal action. This action is so evil that if it is ever discovered it will cause me significant difficulties.
My parents cast a huge shadow and anywhere I go people have high expectations of you. If I bring shame on the family, they will respond against me.
When I focus in on details I loose sight of the whole. When investigating I may be able to notice the tiniest scratches and scrapes, but I might miss the guy with a knife walking up behind me.
I am so good at my job that the head of the guard of my home city got jealous. He framed me and ran me out of town.
I have studied betrayals so often that I inherently don't trust all but my inmost circle... they I watch continually expecting betrayal.