[Steve_Seattle]

This series of bombings is beginning to remind me of the TV series “Numbers,” in which a math wiz solves crimes by detecting patterns in seemingly random events.

[Sacajaweau]

I agree.....the common thread in all these is that they are all delivered on a hit & run basis.

Time of delivery seems to be relevant....4 out of six were likely delivered just before twilight....just as house lights were beginning to go on.

Since a couple picked them up early on their doorstep, perhaps the perp even knocked on the door....or they heard the "vehicle".

I think there's going to be an arrest within the next 24 hours.