The two accused in serial killings of children in Noida's Nithari village underwent brain mapping and polygraph tests at the Directorate of Forensic Sciences in Gandhinagar on Saturday.
The tests were conducted on businessman Mohinder Singh Pandher and his servant Surendra and the process was expected to go on till late in the night, DFS Assistant Director S L Vaya told reporters.
The duo, brought to Gandhinagar for forensic tests on Friday, have been accused of killing several children and dumping their bodies behind Pandher's house in Noida, a township near New Delhi.
Vaya declined to divulge any details regarding the findings of the tests conducted so far on the accused.
About Friday's test, Vaya said detailed psychological profiling of the accused was carried out.
Forensic tests are aimed at digging out vital information and leads from suspects using scientific equipment.
When the accused were quizzed outside the hospital by mediapersons on the allegations of cannabalism and murder, they chose to maintain silent and quietly walked away.
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Coverage: Noida serial killings