MEERUT/LUCKNOW, May 19 -- The Central Bureau of Investigation (CBI) on Monday arrested the alleged triggerman in the high-profile killing of Chandranath Rath, personal assistant to West Bengal chief minister Suvendu Adhikari, from Muzaffarnagar. The arrest comes days after a West Bengal Police SIT detained another suspect in Ayodhya during the early stages of the multi-state probe. The accused, identified as Rajkumar Singh of Ratopur village in Ballia district, was intercepted near the Chhapar toll plaza while reportedly returning from Haridwar with his family, officials said. CBI teams, acting on technical surveillance and intelligence about his movements, laid a trap and took him into custody without resistance. He was produced before the chief judicial magistrate, which granted the agency a 24-hour transit remand for questioning and transfer formalities. The FIR in the case was registered by the CBI on May 12, and the agency has constituted a seven-member special investigation team (SIT) led by an officer of DIG rank to probe the killing. The latest arrest follows the arrest made on May 10 by the West Bengal Police SIT of another accused, Raj Singh, who was picked up in Ayodhya after a multi-state manhunt. Raj Singh is a native of Ballia now residing in Buxar, Bihar, and has been linked to logistical planning. Officials said Rajkumar Singh is suspected to be the main shooter. His arrest follows disclosures by two earlier detainees - Vishal Srivastava and Mayank Mishra, arrested from Buxar district - which helped map the network involved. Rath was shot dead in Kolkata on May 6, triggering a probe that now spans West Bengal, Uttar Pradesh and Bihar. In its initial inquiries, the Bengal SIT relied on call detail records, location analysis and digital surveillance. Raids were carried out in Ayodhya and Pratapgarh after leads pointed to possible Uttar Pradesh links relating to the vehicle used in the attack. Officials said a vehicle associated with the crime bore a number plate registered to Siliguri resident James Williams. Williams had reportedly advertised his Nissan Micra for sale and received queries from UP, prompting suspicion that the attackers used cloned or fake plates to conceal the real car and evade detection....