Killer Seifeddine Rezgui (24), over a short period of time went from being a fun-loving lad to a deranged, bloodthirsty mass murderer.

We know now that he was a follower of Islamic State, which wreaked havoc in Libya, Syria and indeed in the US. Remember the Boston bombings.

His distraught father finds it almost impossible to understand the ideology behind this extreme Islamic cult.

These lone wolf attacks by deranged Islamic fundamentalists can occur anywhere and at any time.

SECURITY

It is proving an almost insurmountable challenge for security forces across Europe to combat this growing and deadly menace.

Last January we had the attack by the same fundamentalists on the offices of satirical magazine Charlie Hebdo in Paris.

On the same day as the Tunisian massacre, another Islamic fanatic cut his boss's head off and impaled it on a fence flanked by two IS flags in France. IS was also responsible for the bomb attack - on the same day - in Kuwait that left at least 30 Shiite Muslims dead in a mosque.

This terrorist organisation has now taken centre stage with its death cult and hate-fuelled ideology. The world is a much more dangerous place.

My prayers and condolences go out to the three Irish people - Lorna Carty and Laurence and Martina Hayes - and all the other innocents who died in that terrible massacre.

My happy memories of that lovely holiday in Tunisia have been spoiled forever.