On 19 March 1987, a group posing as CBI officers executed the fake income tax raid on the Opera House branch of Tribhovandas Bhimji Zaveri (TBZ) in Mumbai. This case remained unsolved.
Jewellery and cash totalling Rs 3 to 3.5 million were stolen from store.

http://en.wikipedia.org/wiki/1987_Opera_House_heist