The callers are located in India and Pakistan.  They are outside US jurisdiction.  Call blocker might be of some help.  Also don't pick up on numbers you do not recognize, or where there are caller IDs that seem odd.  Or where there is no caller ID.

You have to:
(1)  Find them.  Pretty hard to do with over a billion people on the Indian sub-continent.
(2)  After you  find him or her you have to prosecute them.  But in order to do that, you have to extradite them to the US.
(3)  Then if (by some miracle) you manage to extradite them to the US,   you have to try them.  Then hope for a guilty plea.
(4)  Then, even if found guilty, since most Indians are dirt poor, a US prison would be a step up.

None of this stuff is going to happen, so I'd invest in a call blocker if I were you.

The guy had a thick Indian accent. Wow! They almost got me. Lol

I remembered a news report on television that warned about this telephone call.  I received the call and know that it is a scam.  I hope that people who get this call will research it.  Also, the call was a recording.

The IRS does not notify people be telephone.  If the IRS has an issue, they notify the person by mail.