Sources said stone trader Tulu Mondal has invested in Switzerland and Dubai. Investigators suspect that revenue from illegal stone quarrying, sand mining, and cross-border cattle smuggling was routed to purchase assets abroad. (File Photo)A West Bengal Police Special Task Force (STF) team on Wednesday conducted a search operation at the residences of stone trader Tulu Mondal’s brothers-in‑law, intensifying the investigation into the massive cash and gold haul linked to him. According to sources, STF personnel searched the homes of Mondal’s brothers‑in‑law, Mintu Sheikh alias Mohammad Samsul Alam, and Nurul Islam. Investigators have alleged that Tulu, who is known to be a close associate of Trinamool Congress heavyweight Anubrata Mondal, has amassed wealth by siphoning government funds.