Authorities on Thursday responded to hundreds of bomb threats sent to businesses, government buildings, schools, and news outlets across the country, according to multiple reports. The FBI is now conducting a national investigation, as the threats were sent to numerous cities—though the threats have been assessed as likely not credible. Several buildings in Oklahoma, Idaho, Utah, Illinois and New York were among those evacuated after receiving threats via email, authorities said. In New York City, the NYPD said it had received “multiple bomb threats that have been sent electronically to various locations.” “These threats are also being reported to other locations nationwide & are NOT considered credible at this time,” the NYPD added. The police department quickly followed up, revealing that the emails are part of a suspected bitcoin scam. “Please be advised—there is an email being circulated containing a bomb threat asking for bitcoin payment,” NYPD tweeted. “While this email has been sent to numerous locations, searches have been conducted and NO DEVICES have been found.”

The email, which was sent out in different variations, threatens that an unidentified person will detonate a bomb if targets do not pay the attacker in bitcoin, NYPD official said. “I want to offer you a bargain. 20.000 dollars is the cost for your life. Pay it to me in BTC and I warrant that I have to withdraw my mercenary and the device won’t explode,” reads one variation of the email. “But do not try to deceive me- my assurance will become valid only after 3 confirms in blockchain.”