Most of those involved in Sunday's violence in JNU are suspected to be insiders who went knocking on specific doors of certain hostels, a senior police official said on Tuesday.
With no arrests made even after two days of the incident, Delhi Police's Crime Branch sought details from the varsity administration of students and faculty members who were injured in the violence to record their statements and requested for a separate room in the campus for carrying out investigation related to the attack.
It also issued a public appeal seeking pictures, footage or any information related to the violence.
According to preliminary investigation, "most of them involved in the violence were students (insiders) and they went knocking on the specific doors of certain hostels", the official said on the condition of anonymity, adding the involvement of friends of the JNU students in the violence is also being probed.
The main focus of the investigation will be on the Periyar and Sabarmati hostels where the violence was reported, the official said.
The Crime Branch team probing the JNU violence spoke to the warden and some boys (students) of the Periyar hostel where young masked people unleashed mayhem on Sunday.
The team also met JNU Vice Chancellor Jagadesh Kumar to discuss the events that unfolded on Sunday.
According to police, its team has not been able to get in touch with the 34 people which includes students and teachers who were injured in the attack as they have returned to their respective hostels.
"We have been told that some of them have gone home while others seem to have residences of their friends, relatives or acquaintances," the officer said.
Police said they have also asked for contact details of those injured in the attack so as to record their statements.
Besides, police have also sought list of wardens of specific hostels and their contact details in connection with the probe.
The Crime Branch has written to the JNU administration requesting for a separate room in the Administrative block of the University where they can interact with the witnesses and victims of the incident, the official said.
"Since there are no CCTV cameras installed inside the hostel, we are relying on the accounts of the witnesses and the videos that were shot by the witnesses on their mobile phones. We will also have to verify the authenticity of the videos that went viral on social media platforms," the officer said.
According to the official, the Crime Branch has not yet identified those involved in the violence since they have not been able to speak to the injured yet.
The investigation into the violence so far, has not revealed use of any "code words" by the perpetrators to communicate with each other during the attack, the officer said.
Meanwhile, the two FIRs registered in connection with the vandalism at JNU campus were on Tuesday transferred to the Crime Branch.
The two FIRs were filed by Delhi Police on the night of January 5, within a span of few minutes, after taking cognisance of complaints filed by JNU authorities naming office bearers of student union including its injured president Aishe Ghosh in connection with the vandalism.
Teams from Physics, Chemistry and Biology divisions of the Forensic Science Laboratory (FSL) visited the university and looked for clues, sources said.
The Physics team will collect evidence such as rods and stones used by the masked mob to attack students and teachers at the university, while the Chemistry team will collect samples of chemicals, if there are any. The biology team will collect DNA samples, among other evidence.
A team of photo experts from the FSL was also present at the campus.
Delhi Police has requested the FSL to also send a computer forensics team to analyse CCTV footage and it is likely to visit the university on Wednesday, according to the sources.
"A Crime Branch team of Delhi Police is probing the case in a scientific and professional manner and evidence is being collected and are probing all the angles," said Anil Mittal, Additional PRO of Delhi Police.
The Special Investigation Team (SIT) of Crime Branch is headed by Joy Tirkey.
Joint Commissioner of Police (Western Range) Shalini Singh, who is heading a fact-finding committee to probe the incident, also visited the JNU campus and spoke to students and teachers.
Shalini Singh visited all the spots and interacted with the students on campus.
Delhi Police's Crime Branch issued a public appeal urging "all those who are witnesses to the incident or have any information about the incident or have captured any activity on their mobile phones or camera" to "come forward and give their statements/footage/picture in their possession to the SIT".
On Sunday, a mob of masked goons stormed the JNU campus in south Delhi and targeted students in three hostels, assaulting students with sticks, stones and iron rods and breaking windows, furniture and personal belongings. They also attacked a women's hostel.
Security has been strengthened in the campus following the violence. Police personnel in large numbers are present near various gates of the university to ensure that no untoward incident takes place.
Police has barricaded the gates and only visitors with valid identity cards are being allowed entry.
An FIR has been registered against unidentified people in connection with the violence.
The Crime Branch, along with the local police team, had visited the campus on Monday to collect evidence, including CCTV footage.
The agency is scanning all CCTV footage of the incident and also the video clips uploaded on social media and circulated on WhatsApp, according to police.