Hoshiarpur native Jyoti Rani, 24, who was allegedly killed by Himachal Congress MLA Ram Kumar Chaudhary and his accomplices, had struggled against them inside their car before she was eventually crushed under a truck.
Hair that stuck to her sweater as a result of the struggle could prove to be the key clue now.
Cops will match the hair with those of Chaudhary, who was sent in police custody for another four days by the court of chief judicial magistrate Bhawna Jain. The court, while giving permission for the matching, said the samples should be taken in the presence of a doctor or medical board.
Jyoti, who was allegedly sexually exploited by the 43-year-old Doon MLA and his men for two years, was found dead in Sector 21 of Panchkula on November 22. After the probe trail led to Chaudhary over his alleged relationship with the victim, he surrendered on January 8. The other accused are absconding.
The police have also taken handwriting samples of Chaudhary to match with the bank slips through which money was transferred to Jyoti's account from Baddi, Chaudhary's hometown.
Meanwhile, as the Skoda sedan (HR49 B-7171) allegedly used in the crime was recovered from Baddi, police said Chaudhary had removed most of the evidence by washing it. So he now faces section 201 (disappearance of evidence) of the Indian Penal Code too.
The police told the court that as per Chaudhary's interrogation and "confessional statement", Jyoti fell unconscious due to injuries inflicted on her in the car.
She was thrown on the road in a secluded place in Sector 21, Panchkula, and Chaudhary's accomplice Paramjit called a truck. Driver Tilak Raj crushed Jyoti's head under the truck as per the plan to make it look like an accident, it is alleged.
Though Chaudhary's lawyer AS Sukhija said the MLA had given no such confessional statement, police sought his remand to find the truck and arrest co-accused Paramjit, Dharampal, and Gurmeet.
The police are also to recover the mobile phone in which Chaudhary operated a SIM card that he used to contact Jyoti. The SIM card was allegedly bought on a fake ID.
The court handed Chaudhary to the police till the next hearing on January 18.
The police also cited Chaudhary's alleged confession to say that he had developed intimate relations with Jyoti, and impregnated her too.
Her abortion was carried out at Jindal Nursing Home, Sector 20, Chandigarh, where Chaudhary is said to have accompanied her posing as her husband.
Interrogation allegedly revealed that since the abortion, Jyoti was asking Chaudhary for more time, and threatened to make the relationship public.
At this, Chaudhary made a plan with his associates to kill her after the Himachal assembly elections, which were held on November 4.