Moninder Singh Pandher and Surendra Koli, the prime accused in the Nithari serial killings, were on Thursday remanded to 14 days CBI custody.
Special CBI Judge Sapna Misra granted fresh remand of the two accused for their further custodial interrogation.
The CBI, while seeking further remand also produced a few documents related to the investigations during the last 14 days custody of the duo before the Special Court.
The Central probe agency had taken the custody of the two accused on January 11 from the Uttar Pradesh Police and registered a total of 19 cases against them.
The Uttar Pradesh government had announced the CBI probe into the gory killings on January 6 after political as well as public furore over the killings.
The police had on December 29 recovered skulls and human remains from a drain behind Pandher's D-5, Sector 31 residence in Noida unearthing the serial killings of children and women allegedly by him and his domestic help Koli.
The two accused were severely beaten up by an angry mob while being taken to the lockup earlier in the day after their production before the court.
Pandher fell unconscious after the thrashing while Koli whose face was muffled escaped the full brunt of the mob fury.