A warning to be on the lookout for a new type of scam that's been going down at Flint-area gas stations.

Scammers offer to fill someone's tank in exchange for $20 in cash, saying they'll pay for the fill-up with a credit card inside the gas station. The cards -- likely stolen -- are then declined, leaving the victim with an empty tank and a wallet that's $20 lighter.

In the video below, Mark Giza tells WJRT he witnessed the scam at the 1-Stop at Fenton and Atherton Roads.

"We went in and we noticed the clerk was like bustling, trying to figure out what was going on," he said. "She stopped the pumps. She said the guy had just ran out with the card because it was reported stolen. The girl at the pump, she was wondering why she couldn't get her gas. And, the clerk's like 'I can't do it, the card was declined.'"

Flint police say it's a relatively new scam so there's no history or open investigation.

Don't be a victim. If something seems too good to be true, it probably is.