CBI has received the reports of the Central Forensic Science Laboratory, which conducted three important tests -- forensic psychological assessment, forensic statement analysis and polygraph (lie-detector) test.
Sources said these tests were done to check the authenticity of the statements given by the five accused -- Pappu, Awadhesh and Urvesh Yadav (brothers) and constables Chhatrapal Yadav and Sarvesh Yadav -- that they were not involved in the alleged rape and murder case.
In forensic statement analysis, experts examine the word choice, structure, and content of the suspects' statements as it is believed that while being deceitful, people use different words, phrases, structure, and content in their statements.
The polygraph test measures the biological parameters of a suspect as it is believed that they change when a person is being deceptive. For psychological analysis, experts put suspects through a number of questions to ascertain whether or not the person is telling the truth.
The forensic examination results show that the statements of the five accused claiming they did not have any hand in the crime are correct. Highly-placed sources made it clear that the reports of lie-detector tests done on the parents and family members of the two teenaged girls are yet to arrive.
The two girls were allegedly raped and their bodies found hanging from a tree. They said that although the results may not be admitted as evidence in court, the agency has taken note of the tests and will try to develop corroborative evidence from these.