We all have a level of fetish, and it is perfectly fine, it makes life exciting and somehow influences our preferences and tastes in choosing romantic partners. The problem starts when one becomes obsessive and destructive to self and to those around. Like the case of the Kericho man.
So how does one find himself a full-blown fetishist? Often starts as a stimulator during masturbation, paired during sex as often as possible until it becomes the primary source of sexual arousal. For the person to reach a climax or be 'sexual' he must have the object in possession and within the vicinity. This is the psychological concept of conditioning.
One indubitable law in psychology is that all behaviour is learnt. Conditioning, in Behaviour Science, is the process by which the person becomes accustomed or acclimated to a certain behaviour. Whenever a behaviour is rewarded, it gains more root. Stealing panties were rewarded with sexual satisfaction and that is why the person indulged despite the consequences.
So how does one overcome a Fetish? Well, a behaviour learnt can always be unlearnt- if you have a fetish you're uncomfortable with, apply the same concept.