A mass shooting in which 15 people were killed during a Hanukkah celebration at Sydney’s Bondi Beach was “a terrorist attack inspired by Islamic State,” Australia’s federal police commissioner Krissy Barrett said Tuesday.

The suspects were a father and son, aged 50 and 24, authorities have said. The older man was shot dead while his son was being treated at a hospital on Tuesday.

A news conference by political and law enforcement leaders on Tuesday was the first time officials confirmed their beliefs about the suspects’ ideologies.