Bob has $100,000 in an account at First Example Bank. Bob robs the bank, taking $50,000, and he escapes. He is never caught, but the bank is 100% sure that he is the one who robbed the bank. Can they deduct $50,000 from his account to cover the loss, effectively turning the robbery into a withdrawal? Obviously, this doesn't make the robbery any less illegal, but it does offset the bank's loss.
If there has been no trial establishing Bob's guilt, the bank does not know that it was Bob who did rob the bank.
Even if the bank has Bob on the security video feed, claiming that, "As my name is Bob, I will shoot anyone who does not follow my instructions", and Bob left behind his driver's licence at the heist, the bank does not know that it was Bob.
The bank could sue Bob in a civil action in order to get the money back. It would have to follow some procedures to notify Bob of the lawsuit and, if he did not appear, it would win by default. If Bob were to appear, he could make his case about why the bank should not be entitled to that money ("It was not me" / "I only took $1,000" / whatever).
After the trial had happened, the bank still could not take the money right away. Maybe Bob would offer some other assets worth $50,000 to pay the bank.
After it had become evident that Bob was unwilling or unable to comply with the payments, then the bank could ask the court to seize Bob's assets. The court would decide which assets could be seized, would order to have them seized, and then would provide them to the bank.
That does not mean that Bob would be free to use his $100,000 during this time. Before the trial is over, the bank could request the judge to freeze Bob's account, as a way of ensuring that he does not withdraw the money from it. The judge would evaluate the likelihood of Bob losing the trial and refusing to honour it (and whatever Bob's lawyer's objections to this are) and decide on the issue. But that would only affect Bob's ability to use the money, not his ownership.
I don't know if it's normal or not, but my Credit Union's membership agreement says that they can permanently freeze the account without warning to members who "cause a loss". They can also seize money for "obligations" though I don't know if that requires a trial or not.
At any time and without notice we may suspend or terminate your Account or remove you from any Account on which you are an Authorized Signer or a Joint Account Holder or may require you to close your Account if...
g. You cause a loss to BECU...
...Suspensions may take the form of a temporary or permanent “hold” or “freeze” on your Account at our discretion without prior notice to you...
... If we terminate or close your Account, we will mail to the Primary Account Holder all funds in the Account, less any obligations owed to BECU by any Account Holder...
Bob has made a withdrawal from his bank.
The fact that he failed to complete a withdrawal-form may be relevant in some future civil case, but is unlikely to have any force. The fact that he was committing a crime at the time may also be relevant in some future civil case, but not in his favor.
The fact that he was withdrawing his own money may be a factor in his eventual criminal trial and sentencing, but is unlikely to have much effect: normally the conviction and sentencing is not reduced even when the bank robber gets away with zero cash.