The Rapid Action Battalion said the bus of Basumati Transport in Mirpur's Kalshi was set on fire on 18 November for Tk7,000. 

The video and photo of the burning bus were sent to local leaders of "a political party," said RAB's Legal and Media Wing Director Commander Khandaker Al Moin during a press conference held on Tuesday (21 November) afternoon at the RAB Media Center in Karwan Bazar.

RAB have already arrested four — Ali Mohammad Chan, 27; Md Sagor, 25; Md Al Amin Rubel, 29; and Md Khorshed Alam, 34 — on Monday (20 November) night in connection with this incident.

Khandaker Al Moin alleged that Chan, one of the arrested individuals, planned to set fire to buses in Mirpur and the surrounding areas of Pallabi under the direction of top leaders of their party.

He further claimed that Chan recorded and sent pictures and videos of the burning bus to the top local leaders of the political party.

"Each individual involved in the arson attack was supposed to receive Tk10,000. But Sagar and Al Amin were given only Tk7,000 each, as admitted by Chan," Khandaker Al Moin said. 

The RAB made the arrests after analysing videos broadcasted in various media and from CCTV footage. 

The RAB said all of them already have several existing cases against them. 

The Basumati Paribahan bus was set on fire around 11:30pm in Mirpur's Kalshi on 18 November.

Earlier on 6 November, the Counter Terrorism and Transnational Crime (CTTC) unit of the Dhaka Metropolitan Police (DMP) said a local Chhatra Dal leader had been offering a bonus of Tk3,000 for those who set fire to buses. 

The leader, who has been arrested, also allegedly doubled the bonus money for the second phase of the blockade.