The police had recorded his statement two days back. Senior sub-inspector Ashish Kumar Singh, the investigating officer, said the eyewitness has agreed to record his statement before a magistrate.
On Wednesday, the police filed the chargesheet in the case against two accused, Uday Swaroop, 21, a student at the institute, and his friend, Yashveer Singh Sandhu, 35, a laboratory technician. Singh said the chargesheet had been filed on charges of attempt to rape and murder. Swaroop is the grandson of retired IAS officer Prem Kumar, president of the Dayal Bagh Satsang Sabha, which runs the institute.
Singh said the eyewitness is known to the victim's family.
"He said on March 15 he went to the laboratory to meet Neha. He claimed to have heard the girl screaming and had seen both arrested accused hitting her. He says he was scared and quietly left," said Singh, adding that the youth said he did not inform the police then because of fear. Now, he has come to the police on his own.
Neha, 27, was working on a research project on antibodies. Her body was found in the laboratory with 12 deep cuts, inflected with a paper cutter and a surgical blade.
The police came to know about the death the same day after they found Neha's abandoned car, with a cellphone number written on a paper. The number turned out that of her father Rashpal Sharma in Delhi. Later, the police found Neha's laptop from a garbage bin near the lab.
On April 23, the police arrested the two accused and claimed that the murder was not planned. They said Swaroop killed the girl after she reisisted rape and Sandhu helped him in destruction of evidence.
The police recovered blood soaked hair strands from the murder site. In forensic tests, the hair proved to be those of Uday Swaroop. They said there are also two witnesses who claimed to have spotted Yashveer driving away the girl's vehicle from the campus after the murder.