The crime branch central unit has arrested five robbers who were involved in the Rs 1.5 crore heist at Ambika Jewellery store in Ghansoli of Thane district. The robbers were arrested from their native place Rajsamand in Rajasthan using technical surveillance. A part of the loot - about 2 kg gold and 21 kg silver - has been recovered from the robbers. On November 14, three robbers had threatened the jeweller and his employees with knives and firearms and had locked them into the bathroom after gagging them. Thereafter, the robbers decamped with huge quantities of gold ornaments and silver bricks.