Like Redouane, the man arrested in Limerick is of Moroccan descent and had been illegally working here as a chef for some time.
It is understood that the Limerick-based chef received Redouane’s identity information on the black market and it was ‘chance’ that he ended up with this man’s identity.
An investigation was carried out by the Garda National Immigration Bureau and it is believed gardaí are satisfied he is not connected to the terrorist in London whose identity he was using.
A source said: “This man had used false ID to acquire a PPS number in order to work. It seems he got Redouane’s PPS number by chance and he used his own photo on the identity card with Redouane’s name.
“Before coming to Limerick he worked in the south-east of the country. He worked as a chef.”
It appears his name came up on the welfare system data and gardaí were alerted.
The man was released yesterday afternoon, having been in custody since his arrest on Monday. A file has been sent to the DPP.
Fianna Fáil spokesman Niall Collins said the arrest shows up major flaws in the welfare identity system. “It now seems that PPS details of individuals are being sold on to illegal immigrants who want to get work. This is worrying from a security point of view and also in relation to fraud,” he said.
“This only came to light because a major trawl has been conducted once it emerged that the killer, Redouane, had lived and worked as a chef in Dublin and was moving over and back to the UK.
“The Minister for Justice Frances Fitzgerald and the Minister for Social Protection Leo Varadkar must make immediate and detailed statements as to what has been going on.
“This has now come to our own doorstep. Islamic fundamental terrorists are now using Ireland as a base for their activities in the UK. We are seen as an easy open door to the UK as our security services have been decimated with cutbacks.”
Meanwhile, security services in Britain are to launch a review into the atrocity amid mounting questions for police and MI5.
The third attacker has been named as Youssef Zaghba, an Italian national of Moroccan descent, who was living in east London.
The latest developments come with counter-terror agencies already facing intense scrutiny after it was revealed another member of the terror gang, Khuram Shazad Butt, 27, had been known to security services.
Butt was investigated by officers in 2015 but they found no evidence he was planning an attack and he was “prioritised in the lower echelons of our investigative work”, police said.
The disclosure means perpetrators in all three of the terrorist outrages to hit Britain this year had at some point appeared on the radar of security agencies.
British Prime Minister Theresa May said a review had been launched after the Manchester bombing last month and she expected the same process following Saturday’s rampage.
Butt and Redouane, who also used the name Rachid Elkhdar, lived in Barking, while Zaghba worked in a restaurant in London.
A teenager who went to the same gym as London Bridge knifeman Butt said he seemed like the “last person” to carry out an attack.
Abdullah Mohamed, 18, said he had sparred with Butt at the Ummah Fitness Centre in Ilford. Butt would box at the gym and also occasionally sit on the front desk and take payment, said Mr Mohamed.
The gym said Butt trained there “occasionally”, but that they “do not know him well, nor did we see anything of concern”.
Mr Mohamed identified Butt from a police-issue mugshot and said: “I saw him here a few times. He just used to tell us the rules about the gym. He was a quiet guy.
“He did a little bit of boxing. He used to just help out little kids, like 10-, 12-year-olds when they used to come over, and he sparred with us once or twice.”
Asked if Butt seemed to be training in preparation for an attack, Mr Mohamed said there was “nothing” to suggest as much.