Investigation is a subtle process, requiring patience and fine analytical ability, as well as a skill in cultivating one's sources. When torture is condoned, these rare talented people leave the service, having been outstripped by less gifted colleagues with their quick-fix methods, and the service itself degenerates into a playground for sadists.
When you have been just told that the girl you love is definitely betrothed to another, you begin to understand how Anarchists must feel when the bomb goes off too soon.