When are dead bodies discovered?

In Hitman: Blood Money guards can discover dead bodies, which has the effect of raising general suspicion and potentially blowing your disguise (as well as lowering your rating at the end of the mission). While there are specific "body dumps" (such as freezers or cliffs) these can be sparse.

Are bodies only discovered by guards on their default patrol routes, or is there a hidden timer that counts down until a body "in plain sight" (even if hidden in a side room) is discovered?

Solution 1:

The safest way to avoid a body being discovered is to hide it (inside a trunk for example). Why? Most of the time innocent people walk in random paths.