The scammers are foreign - so not much the US Government can do to stop them, other than alerting people to the scam.

it is a scam also this number 206-436-4144

I received a call from this no today 206-436-4708.threatening and accusing.will report to irs

Today, we had a call from 206-436-4708r. The person identified himself as Mark Anderson (and then Mark Watson) form IRS. He threatened me with IRS issues and that there will be a warrant for my arrest.
Thank you everybody for posting this thread on internet.  Now, I know that the call was just a  fraud. I hope the put the b... s in jail.

Unfortunately these callers are probably not even the US. All the red tape gets in the road unless they happen to step foot on US soil.  Occasionally the other country's actually do co-operate but its one of those things that takes time.  We'd love to see all the extortion scammers in Jail..