Essence of Echoes

A serial killer is on the loose, and brilliant FBI agent Julia Gates is on the job.

When victims are found dead in their homes in the middle of the night, Julia and her fellow agents do all their crime-scene detecting and evidence collection by flashlight. Since no one says there's been a power shutdown or a blackout, all we can surmise is that either the victims forgot to pay their electric bills, or the FBI fails to train its agents in the use of a handy device found on the walls of all the fancier houses -- a light switch -- in order to see what they're doing. They must miss a lot of evidence that way.

But, hey, this is a movie in which you hear the following dialog:

"All I know is, the (investigation) went deep."

"How deep?"

"All the way to the top."