Two back-to-back incidents of robbery are giving sleepless nights to the police in the Western Suburbs. While the first theft of jewllery worth Rs 1.5 crore plus Rs 3 lakh cash was reported from Meghwadi, Andheri (East), Rs 50 lakh was stolen from a Bandra residence — both took place last week. But, it’s the similarity in the modus operandi that has cops wondering if there’s a single gang behind the crimes.