A secondary school teacher has been interviewed in connection with the hanging of two paintings of Taoiseach Brian Cowen in two art galleries in Dublin.

The 34-year-old man was questioned by detectives at Pearse Street Garda Station for two hours yesterday afternoon.

He was released without the charge and a file is being sent to the Director of Public Prosecutions.

Gardaí began investigating the case yesterday morning. They identified the painter as a 34-year-old secondary school teacher, who lives in Rathgar in Dublin.

They phoned the man and he agreed to come in to Pearse Street Garda Station to be interviewed.

The man was not arrested and made a voluntary statement.

He also handed over five similar paintings of other senior politicians.

It is understood he admitted painting and hanging the two portraits of Mr Cowen on the walls of the National Gallery and the Royal Hibernian Academy.

The garda investigation into the matter was completed in less than six hours.

It is understood the man may be prosecuted for alleged criminal damage after he was captured by CCTV putting glue on to the gallery walls before hanging the pictures.

Fine Gael justice spokesman Charlie Flanagan has branded the investigation a gross affront to freedom of expression and a waste of garda time.

Mr Flanagan said it was a waste of resources for detectives to be probing 'what amounted to a practical joke that offended the Taoiseach's ego'.

'Today FM has clearly come under pressure to hand over emails about this matter while RTÉ News was obviously browbeaten into a grovelling apology,' he said.

'Freedom of expression is fundamental in a democracy.

'As politicians, we are frequently subject to unflattering comment and depiction but that is part and parcel of being a politician living in a free society.

'The Taoiseach's over-reaction to what amounted to satire is completely over the top.'