- Lalu Yadav had defied three CBI summons in the past
- Son Tejashwi Yadav will be questioned by CBI tomorrow
- Lalu Yadav is accused of irregularities when he was Railways Minister
The CBI had 100 "specific" questions for the former chief minister, who came in a green kurta, escorted by daughter Misa Bharti.
At lunch time, the investigating agency organized a special, low spice meal of jeera rice, aloo chokha (a boiled potato delicacy) and arhar dal for the 69-year-old, careful about his health needs.
Mr Yadav's daughter Misa escorted him to the CBI office. His son Tejashwi is to be questioned tomorrow.
The interrogation is in connection with three acres of premium land in Patna owned by the Yadavs, where a mall was being built until construction was stopped in June.
Lalu Yadav has been charged with facilitating, as the country's Railways Minister in 2006, a contract to a private company to run hotels, in exchange for the land as bribe. The land was first transferred to the wife of a lawmaker of Mr Yadav's party, Sarla Gupta, who signed it over to Mr Yadav's wife Rabri Devi and son Tejashwi at a vastly reduced price, the CBI says.
A tax investigation against the Yadav family has reportedly revealed that the hotel contract and the transfer of land to Sarla Gupta took place on the same day.
The CBI says it has clinching evidence against Lalu Yadav after the questioning of his wife Rabri Devi by tax officials.
The case surfaced in April, when the BJP in Bihar raised allegations that Lalu Yadav's older son Tej Pratap Yadav had abused his powers to sell to the Patna zoo a large amount of soil dug out during the construction of the mall.
Tejashwi had in July refused to quit as Deputy Chief Minister when the allegations raged and the Yadavs were raided by the CBI. Chief Minister Nitish Kumar then ended his alliance with Lalu Yadav and the Congress, saying his conscience would not allow him to continue. A day later, he resumed charge as Chief Minister after resurrecting his alliance with the BJP.
Mr Yadav is facing trial in several fodder scam cases. He has been convicted in one of the cases, after which he has been banned from contesting elections or holding public office for years.
Tejashwi insists he cannot be blamed for a deal dating back to when he was "just a boy who hadn't even sprouted a moonchh".