New Delhi, July 31 - The Bharatiya Janata Party (BJP) Friday demanded the resignation of Buta Singh as chairperson of the National Commission for Scheduled Castes and Scheduled Tribes after the arrest of his son in a corruption case.

'This is a case of open corruption... Buta Singh must resign,' BJP leader Gopinath Munde said after the arrest of Sarobjit alias Sweety Singh by the anti-corruption wing of the Central Bureau of Investigation (CBI).

Reacting to the issue, Communist Party of India-Marxist (CPI-M) politburo member Sitaram Yechury said the 'law must take its own course'.

The son of the veteran politician, who has held several important posts, including home minister, was arrested early Friday after he was caught allegedly accepting a bribe of Rs.1 crore from a Nashik-based contractor in New Delhi Thursday.

The CBI is also trying to ascertain Sweety Singh's involvement in some other financial transactions, including hawala deals.

According to CBI sources, the corruption case against Sweety Singh involves a complaint filed by Nashik-based civic works contractor Ramraj Patil.