Did someone accidentally Venmo you money? It might be a scam.

It seems innocent enough: Someone accidentally sends you money on Venmo and asks for it back.

But don’t send the money back.

That’s the warning Michigan Attorney General Dana Nessel issued to Venmo users this week about an “accidental” money transfer scam.

The scheme involves Venmo scammers using stolen credit cards to send money, then reaching out to users saying it was a mistake and they can send the money back to their account. But when Venmo discovers the transaction came from a stolen credit card, the app can take the money from a user’s account while the scammer keeps the money.

“Scammers are constantly evolving their tactics to exploit consumers,” Nessel said. “Remember, it’s always best to use an extra degree of caution with any transaction involving someone you do not know. If you believe you have been a victim of a scam, please do not hesitate to reach out to my department.”

Nessel also warned about other money transferring scams.

In one, scammers can impersonate a person’s bank by issuing a “suspicious activity” alert and directing them to send money to themselves or the “bank’s address” to reverse a transaction. Fraudsters can also pretend to be a fraud department and ask people to confirm their bank account username, credit card data or Social Security number. Or scammers can use stolen credit cards to buy big ticket items, which leaves sellers without items or the money.

The attorney general reminds people to never share personal information, don’t treat money transferring services like cash and don’t pay for products until they’ve been received. Anyone who has been the victim of a scam can file a complaint with the Federal Trade Commission.