Explanation: <em>Detect</em> and <em>perceive</em> are pretty objective, neutral words describing the action of getting to know something rather passively, and <em>find</em> is the result of an active process (searching), but it has no negative connotations. Snoop implies looking, detecting and trying to find things, but in a sneaky, intrusive way; it will carry the negative connotation of spying in most contexts.
