NSW Police investigate whether criminals involved in some of Sydney’s anti-Semitic attacks were hired by an underworld network in exchange for payment.

A Sydney, Australia childcare center was set on fire and vandalized with anti-Semitic graffiti on Tuesday morning, in the second such incident in four days. The attack took place around 1:00am local time in the city's east, near a Jewish school and synagogue.

As authorities investigate whether foreign actors are paying Australians to commit acts of anti-Semitism, experts are warning they won't be easy to track down.