It's been reported that a number of bank personnel were convicted for LIBOR rigging, although quite a few more were acquitted.
Barclay's CEO and chairman both resigned following the scandal, but apparently were not prosecuted.
So what was the highest position held in a (large) bank that was convicted in the LIBOR rigging insofar? How many hierarchy steps were these guys away from the C-level execs of the big banks involved? Wikipedia also mentions some cases are still ongoing, so a similar question can be asked about mere prosecutions.
Note that the fines paid by the various banks involved in the LIBOR manipulations both to US and EU regulators have been numerous, too many to repeat here, Wikipedia has a timeline (see previous link). At Deutsche Bank nobody was individually prosecuted, but the deal with US did involve (besides the $2.5B fine) dismissal of specific personnel from the bank. The NYT reported that documents obtained did reveal some level of knowledge at VP level:
Inside Deutsche Bank, there was widespread recognition of the problem, the authorities said.
In 2009, for example, a Deutsche Bank vice president wrote to a trader that the Tokyo interbank rate “is a corrupt fixing and D.B. is part of it!”