Spanish anti-corruption prosecutors have asked for the so-called "Carol" case to be filed. The case has been open at the National Audience court since the revelation of conversations between Corinna zu Sayn-Wittgenstein and former police officer José Manuel Villarejo. The prosecutors don't believe that the revelations about alleged activities by former king Juan Carlos I would be "susceptible to investigation in the criminal courts".
"The details, beyond their possible fiscal significance, are not sufficient to start a criminal investigation which would be prospective in nature and which dates back to when the then-king Juan Carlos enjoyed immunity as head of state," they say in a statement.
Nonetheless, the treasury reserves the right to investigate the international financial transactions discussed in the conversation, especially those relating to collecting commissions for the construction of the Mecca–Medina high-speed railway. They do, however, note that the king had immunity from prosecution at that time, since it was before his 2014 abdication as monarch.
As such, although prosecutors say that the recording isn't up for investigation, they could start an investigation in parallel to the "Tandem" case, for which Villarejo is currently in pretrial detention, for allegations of corruption in international financial transfers and bribery.