Since we have cats that like to make noise at night... and police don't like to respond to a 911 call only to discover the damn cat knocked over a lamp........... for the third time this month... I will go see what the "bump" was.
We have nite lights all through the house. Every room has at least one. They give enough light to identify friend or foe or cat... and if, after a "bump in the night", the nite light(s) are out in any room then that is the room I will figure the bad guy is in because cats don't turn off lights. If he stays in there until the police arrive... well... good. If he doesn't ... well... I don't know how things will go from there.