Members of the 26-County Garda Special Branch have been exposed on a US website.
The secretive section of the Garda police is responsible for spying on groups it describes as “subversives” and other intelligence targets.
A total of 14 photographs have been published on www.cryptome.org, apparently showing the officers at work outside courthouses and other locations.
In New York the owner of the website said his anti-censorship service was dedicated to exposing all elements of international state secrecy.
The Garda crime and security branch have now downloaded the photographs, which were posted on Thursday and Sunday. Gardai are trying to find out who sent them to the website and why.
However, a Garda spokesman said it was not clear if the publication of the pictures broke any Irish laws.
“There are no threats against the gardai published with these pictures and nothing that would suggest incitement to hatred,” he said. “If a photograph was taken of a garda and it was reproduced in a paper then so be it, there is nothing illegal about that.”
Mr Young said he had no intention of taking the pictures off the website, even if the gardai or the Irish Government asked him to, citing the greater tolerance in the US for free speech.
“In the past the FBI have called me to take down photographs on behalf of other governments. But it is legal in the US to publish.”
He would not reveal who had sent in the photos and said that on most occasions he did not know the identity of the source of material published on his website. He said Cryptome had no way of knowing if the individuals in the photos were actually members of the special branch.
“Since we are not professionals we don’t know if they are accurate but we put them up and leave it to people to decide if they are true ... It is good to have debate about this type of stuff.
“Principally we have a position against government secrecy, and that applies to any government whether it is Britain, Japan or Ireland. So we do what we can to stop this type of secrecy by publishing the photographs.”