A garda based in Finglas has been arrested on suspicion of selling intelligence to members of a criminal gang.

The garda's house in Finglas was raided on Friday at 1pm and he was arrested and taken to Balbriggan station. His girlfriend, also in her 40s, was detained and taken to Ballymun station.

The pair were arrested on suspicion of selling information obtained illegally from the garda communication computer system, Pulse, to criminal gangs in Finglas.

When his home was searched on Friday afternoon his colleagues found a shotgun.

It is an offence under section 62 of the Garda Síochána Act 2005 for officers to be involved in the "unauthorised release of data" collated by gardaí. The Sunday Tribune understands that a criminal in custody told officers the garda had leaked information to him and his associates in return for payment. An investigation was immediately launched.

The garda allegedly sold intelligence to Finglas criminals about their enemies, including addresses where they would hide-out on occasion, the extent of criminality they were involved in, their associates and other general garda intelligence collated on Finglas gangs following extensive surveillance.

Such information could potentially be used by criminals to carry out assassination attempts and the garda's alleged involvement is being taken extremely seriously by senior officers. When the criminal in custody made the allegation, the National Bureau of Criminal Investigation (NBCI) were immediately informed. Detectives at Finglas are also involved in the probe.

The garda and his girlfriend were arrested under section 30 of the Offences Against the State Act and can be held for 72 hours.

Both are expected to be released without charge and a file will be sent to the director of public prosecutions (DPP). The garda could also be facing separate charges of illegal possession of a shotgun but this is not linked to the allegation that he leaked information to criminals.