My Mom's Bank Has Been Holding Her Money?

Location: South Carolina/California/maybe Texas? USA

Hey folks! My mom is dealing with a stressful situation. She was living in South Carolina, and decided she wanted to sell her house and move back to California. She sold her house, received a wire transfer from an escrow company, and then packed up and moved out of state. She stopped in Texas on her drive, where she withdrew a cashiers check from her bank (Truist Bank) for the full amount, anticipating closing out that bank account, since Truist is an Eastern US Bank. She then changed her mind and re-deposited the cashiers check, for fear of losing it in her travels.

Truist told her at this time that her wire was being investigated for fraud, and that if found to be fraudulent it would be returned to sender. This all happened around October 8th. They said they would send a letter with the result of the investigation, and if it was determined to not be fraud, they would send a check with the funds to the address on file.

It has been three months and they have still not sent a communication regarding the investigation, but they continue to send her account statements showing that the money is still in her account, but are not allowing her access to it. Whenever she calls Truist Bank, she gets vague answers ultimately culminating in "we will send you a letter".

Is there a statue of limitations on this? She is on a fixed income and relies on that small nest egg to survive and is really struggling financially right now.

Any advice on how to proceed, what bureau to reach out to, or specific verbiage to use to make progress in this case would be very appreciated. Thank you!

ETA: she filed a report with the FDIC, and they told her they were closing her case and forwarding it to the Consumer Protection Bureau