Besides the 23 people, who were booked under section 302 of IPC, the organisers, Raza Academy and Madina Tul Ilm Foundation, also faced similar charges, police said.
The accused were produced in a local court on Sunday which remanded them in police custody till August 19.
What prompted police to suspect that the violence was pre-meditated was that the word about the event was spread through Facebook, sources said, adding that the investigators might rope in the Cyber Crime cell to find out who posted the online messages and sent the SMSes.
Police suspect the violence to be a "pre-planned" act as participants at the Azad Maidan rally came "prepared" to wreak havoc.
As rioters carried sticks and rods with them, police are now probing from where the weapons were procured and where they were stored before the trouble started. "We are also investigating the source of petrol cans. The mob set the vehicles on fire in a much planned way," a police official said.
According to police, the CCTV footage showing the protesters pouring petrol on vehicles before torching them has been obtained and would be examined.
A special team of Crime Branch, headed by an Assistant Commissioner of Police and consisting of 12 officers, will conduct the investigations.
The rally, held on Saturday afternoon at Azad Maidan in South Mumbai to denounce riots in Assam and also the alleged attacks on a minority community in Myanmar, turned violent with the mob pelting stones, torching vehicles and damaging buses, forcing police to open fire in which Mohammed Umar (22) and Altaf Shaikh (18) were killed.
A war memorial outside the BMC office was also vandalised in Saturday`s incident.
Meanwhile, two police rifles snatched away by the mob from police personnel on Saturday were on Sunday found dumped, along with 19 rounds out of 160 rounds stolen, at Amritnagar in Mumbra, in neighbouring Thane district, police said. "We will question people in the vicinity to find out who dumped these bullets in the area," an official said.
"The Crime Branch would also probe if any inflammatory speech was made by the organisers of the protest rally, where 17 people were present on the stage and five others had addressed the gathering before the violence broke out. We will study their speech," he said.
According to police, a panchnama (spot inspection) will be carried out first to assess the damage to public property and Raza Academy may be asked to pay compensation as per the Bombay Police Act, while the CCTV footage and other available videos would be examined to recreate the developments of last afternoon.
Meanwhile, government railway police (GRP) sources said they have obtained the CCTV footage of the mob boarding local trains from Kurla railway station, alighting at CST and vandalising vehicles there.
Raza Academy and Madina Tul Ilm Foundation had told police in their application seeking permission to hold the rally that they were expecting a turnout of around 1,500.
Some media reports on Sunday pegged the actual figure at over 10,000, police said.
When senior police inspector of Azad Maidan police station on Friday inquired with the organisers if the strength would increase, he was told that they were expecting a crowd of little more than 1,500 people.
According to sources, Madina-Tul-Ilm had allowed Raza Academy to take over as the organiser last week. Police said complete normalcy has been restored following the deployment of over 700 policemen, with no untoward incident being reported on Sunday.