Hours after deadly clashes rocked parts of Dhaka, police detained BNP Secretary General Mirza Fakhrul Islam Alamgir on Sunday morning and also started raids to arrest at least a dozen other top leaders of the opposition party.

Later at night, a Dhaka court sent Mirza Fakhrul to jail after rejecting his bail.

Faced with the crackdown, many BNP leaders have gone into hiding, as the party's Joint Secretary General Ruhul Kabir Rizvi Ahmed announced a three-day blockade virtually from an undisclosed location.

Around 10 hours after detaining Mirza Fakhrul from his Gulshan residence on Sunday morning, police filed at least two new cases, bringing the total number of cases against him to 100.

Also, law enforcers picked up several hundred leaders and activists of the party in nationwide drives following Saturday's clashes that left a police constable and a Jubo Dal man dead and scores injured.

On Sunday morning, just hours after the hartal was announced, the Detective Branch of the Dhaka Metropolitan Police knocked on Mirza Fakhrul's door. He was taken to the Detective Branch office for questioning over the death of the policeman.

After around 10 hours of questioning, he was arrested around 8pm and remained in DB custody until 9pm, when this report was filed. The BNP general secretary was accused in murder and arson cases filed with the Paltan Police Station, said DMP Commissioner Md Habibur Rahman.

Mirza Fakhrul's wife Rahat Ara Begum said, "In the morning, DB police people came to the house. Then, they took the hard disk of the CCTV cameras from both the house and the building. Ten minutes later, they came back and took him with them. Mirza Fakhrul was very ill; his treatment was going on. I can't accept a 75-year-old man being detained like this."

In detective branch custody, Fakhrul refused to have a meal offered by the police. Two of his homemaids took meals for him in separate lunch boxes, and he had his home-cooked food in his custody.

After Fakhrul's detention, police also searched the homes of BNP standing committee members Mirza Abbas and Amir Khasru Mahmud Chowdhury.

Party leaders claimed police surrounded the residences of Mirza Fakhrul, Mirza Abbas, and Amir Khasru Mahmud Chowdhury to arrest them.

Police left the residences of Mirza Abbas and Amir Khasru after an hour of gathering there. Law enforcers said they had gone there as part of their regular operations.

Family members informed them that neither Abbas nor Khasru were at home.

"A team of detectives went to Amir Khasru's house to get him. But he was not found at home," Rifat Rahman Shamim, deputy commissioner of DB Gulshan, told The Business Standard.

Detectives were conducting a search at the residence of BNP Joint Secretary General Syed Moazzem Hossain Alal. The police also searched the residence of Tabith Awal, a member of the BNP National Executive Committee and the mayoral candidate of Dhaka North City Corporation.

Also, at 12:30pm yesterday, they carried out a search at BNP International Affairs Committee member Ishraq Hossain's home in Gulshan and took away his younger brother Ishfaq Hossain and car driver Rajib after failing to find him.

On Sunday, the police and other plaintiffs filed a total of at least 28 cases against around 832 named BNP leaders, which included figures like Mirza Fakhrul, Mirza Abbas, and other high-ranking leaders. These cases were related to charges of detonating explosive cocktails with the intent to harm police officers and confiscate law enforcement personnel's weapons during the BNP's recent rally in Nayapaltan on Saturday. In addition to the named individuals, thousands of unnamed persons were also accused in these cases, which were filed with different police stations. Data from the DMP (Dhaka Metropolitan Police) indicates that approximately 1,480 BNP and Jamaat activists were arrested until the night of October 28, beginning on October 21.

According to the information received, BNP has stated that 960 activists have been arrested in connection with both Saturday's grand rally and yesterday's hartal. A total of 20 cases have been filed. The number of injured activists exceeds 3,000, and there have been four deaths, including one journalist.

Additionally, in the lead-up to the grand rally, more than 2,640 activists were arrested over the course of five days, and 45 cases were filed.

DMP Joint Commissioner Biplab Kumar Sarkar on Sunday said those who were attacking and killing police members will be arrested from anywhere they are found.

Home Minister Asaduzzaman Khan Kamal said cases were being filed against BNP men for the murder of a policeman; snatching duty officers' weapons; attack on the chief justice's residence, Diploma Engineers Institution, police hospital; setting fire to vehicles and attacking journalists.

Both police and the victims of the acts of violence are filing the cases, he added.  

Asked why Fakhrul was detained, the minister said the violence began during the BNP meeting at Nayapaltan, which was being addressed by Fakhrul.  

He also claimed neither AL nor the police went to the designated rally venue of the BNP. "They went out of the rally venue and caused pre-planned anarchy."

He also said leaders and activists of the BNP destroyed the CCTV cameras that were installed on the streets.

Kamal claimed BNP activists burned everything they saw using "special flammable liquid."

Police arrested two people on Sunday for their direct involvement in the killing of Constable Amirul Islam Parvez during a clash with BNP in Fakirapool on 28 October.

Gaibandha's Palashbari Municipal Swecchasebak Dal Convenor Shamin Reza was arrested from Gaibandha and Md Sultan was arrested from Demra, confirmed Additional Deputy Commissioner KN Niyoti Roy.

"We will do whatever it takes to ensure punishment of those involved in the murder of Amirul," said DMP Commissioner Habibur Rahman.

Gaibandha's Palashbari Municipal Swecchasebak Dal Convenor Shamin Reza was arrested from Gaibandha and Md Sultan was arrested from Demra, confirmed Additional Deputy Commissioner KN Niyoti Roy.