Pressure mounted on Spanish Prime Minister Mariano Rajoy on Monday as a once-trusted aide gave more testimony before a judge looking into allegations of illegal financing in the ruling party.
Opposition leaders called on Rajoy to step down and a source within his own centre-right People's Party told Reuters discontent was growing with his leadership.
Rajoy, who is fighting an economic recession and trying to plug a hole in the budget, has so far limited the impact of the scandal over allegedly illegal donations by construction magnates that were supposedly distributed as cash payments to party leaders in return for juicy contracts.
At the heart of the scandal is former party treasurer Luis Barcenas, 55, who was jailed in June and charged with bribery, money laundering, tax fraud and other crimes.
A High Court judge questioned Barcenas behind closed doors for more than three hours on Monday after he was transported from jail in a white van.
A lawyer involved with the case told Reuters that the former PP treasurer was expected to turn over documents showing how he ran a secret slush fund at the party for many years.