Sen. Elizabeth Warren called Wells Fargo CEO Charles Scharf "evasive," saying the bank's answers to her questions about fraud across the Zelle payment platform were misleading, "insulting and useless."
Requests for comment from Wells Fargo and Early Warning Services weren't immediately returned.
Jim Seitz, a spokesman for Wells Fargo, told CNBC in October that Warren's analysis is "misleading and inaccurate."
Warren also said the reply she received from Wells Fargo was "wholly inadequate given the scope of the problems."
"But this assertion, which is an attempt to minimize the impact of the problem at Wells Fargo, is false."