The code name Zero refers to an informer in Dawood Ibrahim's stronghold Dongri and adjoining areas. Goodman is another popular name for an informer. When someone praises an informer, calling him a 'goodman', in typical Indian gesturing, he touches his thumb to his coiled index finger making it look like a zero.This is from a new series on Mumbai's underworld in Mid-Day, which also mentions that 'cutting' is police slang for an informer's tip-offs.
He was not aware of their whereabouts, when a khabri gave him a 'cutting' that they were in J J Hospital ward number 18. (Kingpin Khabri: Goss from Mumbai's underbelly, Sunday Mid-Day, 28 Feb 2010)