Scammers impersonating IRS agents have been aggressively pursuing Americans in at least a dozen states this July, and new evidence suggests the scammers have updated their tactics in recent years.

The IRS phone scam is familiar to police departments and federal authorities alike. In the typical version of the scam, a citizen will receive a call from someone claiming to be an IRS agent. Sometimes, they even provide a fake name and badge number. Then, the scammer demands an immediate payment, threatening to issue a warrant for the target’s arrest.

Except, of course, the IRS doesn’t call, text, or email U.S. residents without prior notice, and they definitely don’t ask for immediate money transfers, or else. In fact, that’s how most authorities recommend identifying scammers.

Some other tips for identifying a scam that may threaten the safety of your personal finances:

• Scammers will try and trick you into acting immediately

• Sudden calls without prior notification of an audit or tax problem

• Rude, belligerent, or threatening behavior from the caller

• Scammers often ask you to “verify” your personal information, duping residents into revealing personal information

And after stealing money from innocent victims, some scammers try their luck a second time. This July, the Federal Trade Commission advised consumers that con men were impersonating FTC agents as well. After pulling a successful IRS scam, the con men will call impersonating an FTC agent and offer to help recover money already lost to a scammer, only to fleece the victim a second time.

Also this July, USA Today reports that in addition to the tried-but-not-true phone scam, some criminals are now mailing fake tax forms to residents. These false tax forms often look legitimate at first glace, and some recipients have mailed the form back with money or personal information.