"We are doing further investigation in the matter," a CBI source said.
The central probe agency has got the prosecution sanction against former Railway Minister Lalu Prasad in the matter
In January, the agency furnished the prosecution sanction letter before the concerned court.
The CBI had in October last year charge sheeted 16 accused, including Lalu Prasad, Rabri Devi, and their daughter Hema Yadav.
The CBI had said that during the investigation, it has been found that the accused in conspiracy with the then GM Central Railways and CPO, Central Railways engaged persons as substitutes in lieu of land either in their name or in the name of their close relatives.
This land was acquired at prices lower than the prevailing circle rate and much lower than the market rate.
"The candidates have used false TC and submitted false attested documents to the Ministry of Railways," the CBI has alleged in the charge sheet.
The CBI has learnt in the probe that Rabri Devi and Hema Yadav were gifted lands in connection with the scam by job seekers who were later appointed in railways.
Haridayanand Chaudhary, a railway employee, and Bhola Yadav, the then OSD to former Railway Minister Lalu Prasad Yadav were earlier arrested by the CBI.
Bhola was Lalu's OSD between 2004 to 2009.
The CBI registered a case against Yadav, the then union railway minister, his wife Mrs. Rabri Devi, two daughters, and 15 others including unknown Public servants and Private persons.
"During the period 2004-2009 Yadav had obtained pecuniary advantages in the form of transfer of landed property in the name of his family members in lieu of appointment of Substitutes in Group 'D' Post in different Zones of Railways," the official said.
A number of residents of Patna themselves or through their family members sold and gifted their land in the city in favour of the family members of Yadav and a private company controlled by Yadav and his family and they were also involved in the transfer of such immovable properties.
"No advertisement or any public notice was issued for such appointment of substitutes in Zonal Railways, yet the appointees who were residents of Patna were appointed as Substitutes in different Zonal Railways located at Mumbai, Jabalpur, Kolkata, Jaipur, and Hazipur.
"In continuation of this modus operandi, about 1,05,292 sq. feet of land, immovable properties situated at Patna were acquired by Yadav and his family members through five sales deeds and two gift deeds, showing the payment made to seller in cash in most of the land transfer," the CBI official said.