The CBI on Tuesday started questioning former railway minister Lalu Prasad in connection with the land for jobs scam case where people were allegedly given jobs in the railways in return for land parcels gifted or sold at cheap rates to the Yadav family and associates, officials said. The examination of the RJD supremo comes a day after his wife and former Bihar chief minister Rabri Devi was quizzed at her Patna residence by the agency for nearly five hours, they said.