Police are stepping up their hunt for a serial firebomber who detectives believe is a “freelance” criminal hired by organised crime groups.

Footage captured the moment of an explosion at Vietnamese restaurant Eat Pho on Tuohy Lane in Marrickville in May.

Cameras were rolling as the man pulled up, set a trail then, then set fire to the shop.

At the same location 24 hours earlier, a hooded figure was seen running in and out before the shop went in flames.

“(It’s) so scary, I can’t believe he can do this. So scary,” Eat Pho staff Rita Duong said.

“It’s very dangerous for our restaurant.”

The attack is also being linked to another blaze at Ettalong Beach last August – a tobacconist that was destroyed in a matter of minutes.

“We believe the tobacconist was targeted to eliminate competition,” Financial Crimes Squad Commander Gordon Arbinja said.

But exactly why the same firebug targeted a Vietnamese restaurant 100 kilometres away nine months later, is under investigation by the Financial Crime Squad.

9News spoke to the owner of the Marrickville business, who now says he has serious fears for his family’s safety 

He says he doesn’t know why his shop has been caught in the firing line.

“We believe that these people were recruited by organised criminal networks and work as freelancers for these criminal networks to commit these acts,” Arbinja said.

The arsonist was last spotted in a grey Toyota Hilux.