Murder mystery: What do all these murders in a single month have in common?

Suppose 30 Americans were brutally murdered each month, in the same circumstances but scattered around the country.  Suppose the problem could be fixed quite easily, but one political party blocks the fix, time and time again.

Think the Mainstream Media would put the pieces together, solve the puzzle and tell ya? 

That depends on which party has been blocking the fix, eh?  So if you like to solve mysteries, see if you can figure out the common thread in the stories of 41 similar murders in a single month, earlier this year.

But if you solve the mystery you're cautioned not to tell anyone, as it's Top Secret!  Revealing the secret to anyone is absolutely forbidden, and doing so can get you fired, or expelled from school.