RSBM
Personally I doubt a bank would transfer that large of an amount by phone, plus we have been told MB went into the bank.
Also, a bank won't consider it an account transfer if the target account is in another person's name. In that case it would be a payment to a third party.
If that had been the case, once inquiries were launched about her disappearance, IMO the bank would have cooperated and told police that MB made a payment of $80K to a person named X, with bank account y at this bank z, and police would have followed up.
Instead, they said she transferred the money to her own account and she insisted that when her family inquired after her, as they inevitably would, she didn't want to be found.
IMO, she didn't just mention that in passing. For MB to transfer her $$ to a new account, in a new name, she must have shown someone who knew her (ie recognized her as their customer, not a stranger in a wig) her change of name documents, her new passport, her new bank account documents in her new name, and so forth, before they would agree to do an 'account transfer'.
Similarly, at the receiving end, there's a clear difference between a deposit from a third party, and a transfer from the owner's other account.
Now, possibly that was, or became, a joint account with another person, and that's how her money was taken from her, but IMO it had to be MB who put her own money there. Banks aren't careless or naive about fraud, preventing it is their primary business.
JMO
ETA Forgot to mention matching signatures...