Though banks went back on their proposal to impose fees for using debit cards, the incident is not over for several of the country’s biggest banks. The Los Angeles Times reports that the U.S. Department of Justice could begin looking into the possibility of antitrust violations among the banks involved.

Several of the country’s largest banks – including Bank of America, JPMorgan Chase and Wells Fargo – looked to recoup losses from the new limits on debit card transaction fees in part by charging customers in the range of $5 per month to use their debit cards.

Though the banks changed their plans in the wake of a public outcry and a flood of customers moving their accounts, Representative Peter Welch, a Democrat from Vermont, decried the incident as a likely case of collusion, or at least price signaling.

Welch and several other House Democrats called on the Justice Department to investigate the banks for possible antitrust violations, according to Bloomberg. Assistant Attorney General Ronald Weich responded that the incident would be reviewed for any possible violations.

“Please be assured that if it finds that individuals, banks or other parties may have violated the antitrust laws, the department will take appropriate action,” Weich wrote in the letter.