Police have cracked the murder case of an IAS officer's advocate daughter with the arrest of the watchman of the building where she lived in central Mumbai. "Watchman Sajid Mugal has been arrested last night for the murder and he has confessed to the crime," a crime branch official. Pallavi Purkayastha (25) was found in a pool of blood Thursday morning at her rented flat in 'Himalayan Heights' building at Wadala by her live-in partner Avik Sengupta (26), also a lawyer.