A Dublin-based Spanish waiter killed his partner and two Irish born children in a murder-suicide in Poland just days before Christmas.
Two Dublin schools have expressed their shock at the news.
Victor Marin Del Sol's three children spent a year in schools in Rathfarnham before they moved to Poland with their mother.
The Irish Independent reports that he flew to Poland to spend time with them just before Christmas.
He killed his partner, Ewelina Szwarc, and his sons - Oskar (9) and Christian (7) - while his daughter Maria Victoria managed to escape.
The principal of Scoil Naomh Padraig told the paper that they will be remembered as "lovely, happy children". Christian and Maria Victoria attended the school and Principal Grace O'Neill said: "We will remember them in our prayers."
Oskar was a pupil at Ballyroan Boys School in Rathfarnham and the school's principal, Des Morris, said: "Oskar was a lovely child. He was a nice boy. He spoke Polish and Spanish and had little English, but he was developing well in the language and integrating well.
"It is shocking and sad."
Polish police are continuing their investigation.