The Delhi Police has sent over 50 fresh notices to people, including farmer leaders, in connection with the violence that broke out during the tractor parade on Republic Day, officials said on Sunday.
The Delhi Police had earlier issued notices against 44 people.
The police have identified several people and sent notices to them, a senior police officer said, adding that the process will continue further.
According to the police, some tractors, used during the violence, have also been identified and notices are being sent their owners.
The process of issuing notices is taking time as many people are not residents of Delhi and letters are being to their addresses, police said.
Teams of Delhi Police are carrying out investigations at several locations outside the national capital, including Punjab and Haryana, to apprehend the people who were involved in the violence. They are also looking for those who hoisted flags at the Red Fort, they said.
Teams from the Forensic Science Laboratory also visited Ghazipur, Red Fort and ITO to collect evidences. They have recovered a lot of evidences, including a big rope with knots, that was used to climb on Red Fort, police said.
Till Saturday, the police have received 1,700 video clips and CCTV footage from public so far related to the violence and is taking help from forensic experts to analyse the material and identify the culprits.
The Crime Branch, which is investigating 10 cases related to the violence, including that at Red Fort and ITO, is also examining dump data of mobile phone calls and registration numbers of tractors.
A team from the National Forensic Sciences University has been called to analyse the video clips and CCTV footage related to the violence that left 394 police personnel injured and one protester dead.
On Friday, the Delhi Police had issued an appeal in leading newspapers asking people to share any evidence or information about the violence.
The investigators are also analysing footage and photos taken from drone-mounted cameras and carrying out 3D mapping of the area vandalised at the Red Fort.
Delhi witnessed violence during the January 26 tractor parade organised by protesting farmer unions to highlight their demand for repeal of the Centre's three farm laws.
Many of the protesters, driving tractors, reached the Red Fort while some of them hoisted religious flags on its domes and the flagstaff at the ramparts, where the national flag is unfurled by the prime minister on Independence Day.