I don’t mean to be a fearmonger, but today I would like to take some time to make sure you are aware of a new type of financial fraud that in recent years has been on the rise.

This new fraud involves the theft of tax refunds. Here’s how it works: First, an identify thief starts with a few basic pieces of stolen data: an individual’s name and Social Security number. (This information, unfortunately, is readily available to thieves. In just one incident in 2017, for example, thieves stole from the credit reporting agency Equifax information on fully half of all Americans.) Using this basic information, the thieves then prepare and file a fake tax return in such a way that it appears a large refund is due. This fake tax return carries the victim’s real name and Social Security number but the criminal’s address, allowing the thieves to collect their fraudulent refund check. The thieves do all of this early in the year, before the victim has even had a chance to file their own real return.

While it might seem difficult to engineer this sort of brazen fraud against the IRS, it turns out to be surprisingly easy. Because a taxpayer’s address and finances may legitimately change from year to year, the IRS can have a hard time telling a real return from a fake. As a result, the IRS has over the years paid out billions in fraudulent refunds.

Tax-related fraud is difficult to prevent. Still, there are some steps you can take to protect yourself. Below are four things to understand about how the IRS operates. This information should help you detect common red flags.

1. The first thing to know is that the IRS never emails taxpayers; it uses traditional US Mail. So, if you receive an email purporting to be from the IRS, delete it. Don’t click on any links, and don’t call any phone numbers contained in the email.

2. The IRS will sometimes call taxpayers, but you should be wary of incoming calls. The IRS will almost always precede any call with a letter. In fact, they will normally only call when they haven’t received a response to multiple letters. If you do receive a call from someone claiming to be at the IRS, do not feel any obligation to engage over the phone. Instead, ask them to mail you information. Or, if you prefer to resolve the question more quickly, go to the IRS’s website (www.irs.gov) and call them back using only a phone number that you find there.

3. The IRS will never ask for payment over the phone or by credit card. The only way you should ever pay Federal taxes is by check made out to “United States Treasury” and mailed to one of the Internal Revenue Service Centers.

4. In an effort to combat this type of fraud, the IRS may send you a letter called a 5071C. This letter will ask you to confirm your identify and may itself appear to be part of an attempted fraud. If you get a letter like this, go to IDverify.irs.gov. That page will include an explanation and a phone number for you to call. To be sure you are responding to a legitimate inquiry, call only that phone number.

If you do become a victim of tax-related fraud, I recommend these steps:

1. Notify the IRS using Form 14039. This is an Identify Theft Affidavit and is your mechanism to formally advise the IRS of the situation. As long as you continue to file your real tax return and pay what is (legitimately) due, this affidavit will help you avoid any penalties that might be triggered by the thieves. In addition, the IRS will implement additional security procedures for your future tax returns.

2. You can also call a dedicated department at the IRS, the Identity Protection Specialized Unit. Their phone number is 800-908-4490, and they can advise you on your specific situation.

3. Place a fraud alert on your credit and also review your credit report. Hopefully this will not reveal any additional fraudulent activity under your name, but it’s best to check.

4. Visit the Federal Trade Commission’s website identitytheft.gov for helpful information and advice. With most forms of identity theft, the largest cost to the victim comes in the form of time, energy and aggravation. For that reason, resources like this can help guide you and save valuable time.

Normally, it is my goal to provide useful and actionable advice. In this case, however, I hope you never, ever have any need for this information.