New Delhi, July 31 - It was meticulous planning that helped the Central Bureau of Investigation catch former central home minister Buta Singh's son Sarabjot alias Sweety Singh allegedly receiving bribe. Here is how the agency did it:

It started with a corruption complaint by Ramraj Patil, a civil contractor for the Nashik Municipal Corporation, filed before the CBI Mumbai branch a fortnight ago.

Patil alleged that Sweety Singh had demanded a bribe of Rs.3 crore - the amount was brought down to Rs.1 crore after negotiations - for withdrawal of a case under the Scheduled Castes/Scheduled Tribes (Prevention of Atrocities) Act, filed against him by a group of workers he had employed.

Buta Singh, a veteran Congress leader, is now chairperson of the National Commission for Scheduled Castes and Scheduled Tribes.

Patil promised to cough up Rs.1 crore but also informed the CBI about Sweety Singh's alleged demand.

Highly placed CBI sources said here Friday that after verifying details of the complaint, a case against Sweety Singh, Pune-based Anup Begi and Mumbai-based hawala operators Madhu Singh and Dhunka Singh was filed July 22.

They said Begi reached Mumbai and met Patil Wednesday and collected Rs.1 crore from him in a hotel in Chembur area.