Police in Austria were hunting for clues on Wednesday after a gunman opened fire at his former high school a day earlier, killing nine students and a teacher in a deadly spree that stunned the country.

By Francois Murphy GRAZ, Austria (Reuters) -Austrian authorities were searching on Wednesday for answers to why a 21-year-old gunman shot 10 people in a rampage at his former high school before killing himself,

Police for the state of Styria said at least 10 people were killed and several seriously injured in a high school in Graz, Austria. They said the shooter was also dead.

“Multiple groups continue to congregate on 1st St between Spring and Alameda. Those groups are being addressed and mass arrests are being initiated. Curfew is in effect,” read a post on the LAPD’s social media, sent at 9:09p.m local time on Tuesday night.

For a second night in a row, riots rocked the town of Ballymena in Northern Ireland on Tuesday, lasting into the early hours of Wednesday morning. Protesters used petrol bombs and fireworks as they clashed with the authorities. In response, police used plastic baton rounds and a water cannon.

The Police Service of Northern Ireland announced Wednesday that things are currently quiet in a County Antrim town after violent attacks on police over a two-night stretch left 17 officers injured.

Demonstrators have pelted police with bricks, bottles and fireworks and set vehicles alight in the Northern Ireland town of Ballymena