Mahesh Kulkarni / Karwar December 01, 2009, 1:27 IST About 50 employees are being interrogated. The Kaiga Atomic Power Station (KAPS) authorities have commenced investigation to identify the person responsible for poisoning the drinking water dispenser at the premises with radioactive isotope Tritium, a senior official said today. About 50 employees of the state-run KAPS, about 51 km from the Karwar coast, are being interrogated by the investigation agencies to identify the suspect.