Garda and financial watchdogs are examining recorded phone calls from inside the bust Anglo Irish Bank to determine if executives broke the law.
After three days of leaked conversations at the rogue lender from 2008, the Central Bank of Ireland revealed it was reading transcripts and will be working with the Garda fraud squad.
"The Central Bank is carefully studying the various transcripts emerging. This is something that is viewed very seriously," it said. "The Central Bank will be liaising with the gardai in this regard and is also examining whether or not any breaches of regulatory requirements may have occurred arising from the information contained in the transcripts."
Several tapes of recorded phone calls, published by the Irish Independent, show Anglo's former chief executive David Drumm and other senior bankers laugh and joke about the lender's imminent collapse.
The calls centre around September 30, 2008 when the then Fianna Fail-Green Party coalition brought in a crippling 440 billion euro guarantee for all the Irish banks. Mr Drumm, who fled to the US after Anglo collapsed, is heard laughing "another day, another billion" - referring to the doomed lender losing one billion euro in deposits a day at the time.
Other calls hear how Anglo bankers' joke that calculations for a seven billion euro bailout are pulled "out of their arse".
Executive John Bowe is heard singing Deutschland Uber Alles when conversations swing to the anger felt in Germany and the UK over the guarantee. It is believed the recorded phone calls may have been in the possession of gardai and corporate law investigators since raids in 2009, but that has not been confirmed.
And with anger growing over the content, the Government is under deepening pressure to establish an inquiry with the power to force bankers to give evidence and possibly face findings of guilt. Taoiseach Enda Kenny has said he is adamant a parliamentary probe is sufficient but concedes it cannot deal with criminality. It had been planned to begin in the autumn, despite opposition calls for a Leveson-style approach.
There are also concerns that such an inquiry will be delayed when the trials start next year of three former Anglo bosses on fraud charges - ex-chairman Sean FitzPatrick, former finance director Willie McAteer and Pat Whelan, former managing director.
Amid the fallout former taoiseach Brian Cowen is facing renewed calls to come clean over his contacts with bankers around the time of the guarantee. Worse revelations from internal conversations at Anglo are expected in coming days with suggestions that politicians and a civil servant may be mentioned for the first time.