Got call from fake IRS about fraud

I got a calll today from somebody who claimed to have been from the IRS. According to him, IRS has discovered that I committed some kind of taxpayer fraud on my previous several tax returns. He gave me a case number and throughout this whole conversation I suspected that this was some kind of fraud, but he never asked me for my social security number or for money. Maybe it was because he thought I was not taking the situation seriously enough.

Throughout the conversation he maintained that I'm going to be arrested and taken into custody in the next 40 minutes to 1 hour, additionally my bank accounts and assets will be frozen, my employer notified, and I need to find a criminal attorney within the next hour.

I could hear the voices in the background like it was some kind of a call center. He maintained that in the next 40 minutes or so he was going to transfer the case, as he called it, to the sheriff's department and they would be coming to pick me up. Pretty strange considering that this would be a federal case and this is against everything I know about how the legal system works.

In addition to telling me my case number, he stated several laws and IRS regulations or whatever. It was all relatively vague but he mentioned the number for at least one of those so-called regulations.

He also stated that I could be deported, which is funny considering that I'm an American citizen. He also said that my house will be confiscated. I don't own a house. He advised me not to touch my bank accounts which made me check my bank accounts and change their passwords, just in case. I suspect that they will call me again pretending to be from the Sheriff's department or whatever and tell me that I could make these, so called, charges go away if I pay up.

While thinking how I could find a good criminal attorney and thinking about what I should take with me to jail, I decided to do some checking.

The cursory check on the internet confirmed my suspicions. Apparently this type of fraud has been increasing in frequency in the last year or so, especially against immigrants, recent or otherwise.

Just to be sure, I called IRS and after waiting for about half an hour, talked to a lady who was pretty confused about what I was referring to. Not unexpectedly, IRS doesn't deal in such kind of situations in such a way. It is unlikely they would ever call you. Most likely I would receive a letter or something to that effect.

I hope the scammers call again so that I could mess with them.

Question is how do I report these a-holes and if anything can be done to deal with them.