Details are emerging about the gunmen behind last night's deadly attack at Sydney's Bondi Beach.

15 people were killed and dozens more were injured after the shooters opened fire into a crowd of people celebrating the first day of Hanukkah.

National security expert and Australian National University research fellow Dr Levi West says the father mustn't have raised any alarm bells when he applied for a gun license. 

"Associations that your son has with people is not necessarily sufficient to rule you out of measures. The New South Wales state Government is talking about tightening what is some of the toughest gun laws in the world."

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