A laser microphone might be the source of those dim flashes I have seen in here before, as I just now saw two dim flashes as I sit at my desk.
I have been thinking for a while that the insurgent forces are camped out in one of the houses in front of my apartment. They do not think of themselves as illegal combatants against the US federal government, as they are delusional and are a clear and present danger to the United States, but of course they are a threat to public safety.
The flashes could be the reflection of the laser off certain reflective surfaces in this apartment. The laser beam itself, I guess, is invisible to the human eye.