JPMorgan JPM -2.38%decrease; red down pointing triangle Chase is investigating thousands of incidents of possible check fraud committed as part of a TikTok craze and plans to share the evidence it gathers with police departments around the country.

Users on the social-media platform began sharing videos that showed a so-called glitch at Chase Bank that was allowing customers to deposit big checks and withdraw funds from ATMs immediately, even if sufficient funds weren’t available.

Chase, the largest consumer bank in the U.S., normally allows customers to withdraw a portion of deposited checks before the full check amount clears. However, late last week, a technical error allowed customers to withdraw all of the funds from a check before it had cleared.

Check fraud, which has surged in recent years, is a federal crime and illegal in most states, too. Most check fraud cases in the country are prosecuted under state law.

As part of the scheme, some people wrote checks to themselves and cashed out money they didn’t have, while others cashed checks written from other peoples’ accounts that didn’t have enough money.