Searches in multiple premises in firms and trusts founded by spiritual guru ''Kalki'' Bhagwan has led to detection of undisclosed income of more than Rs. 500 crore, the Income Tax department said on Friday. The undisclosed income covers unaccounted cash receipts of about Rs. 409 crore. A total of Rs. 43.9 crore in cash and US currency worth Rs. 18 crore was seized and the total value of seizure is about Rs. 93 crore, which includes gold and diamonds, a tax department official release said.