Mumbai, July 31 - Sarabjot alias Sweety Singh, son of former central home minister Buta Singh, was formally placed under arrest by the Central Bureau of Investigation (CBI) early Friday for his alleged involvement in a corruption case, officials said.

Sweety Singh was nabbed in New Delhi Thursday by CBI sleuths when he was allegedly accepting a bribe of Rs.1 crore and brought to Mumbai later in the evening.

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

Patil had alleged in his complaint that Sweety Singh had demanded a bribe of Rs.3 crore, which was later brought down to Rs.1 crore, for withdrawal of a case under the Scheduled Castes/Scheduled Tribes (Prevention of Atrocities) Act, filed against Patil by a group of local conservancy workers employed by him.