The bomb disposal and detection squad of West Bengal CID on Monday visited the spot in Burdwan district where a huge explosion took place inside a TMC office on Sunday.
"The team of bomb disposal and detection squad visited the spot today and collected some samples," a senior CID official said.
A Trinamool Congress office in West Bengal's Burdwan district was on Sunday destroyed in a huge blast suspected to have been caused by explosives stored inside the structure.
The blast took place at the Pichkudi Dhaal TMC office in Ausgram in the evening.
Meanwhile, West Bengal state BJP president Dilip Ghosh demanded an NIA investigation into the case.
"The state should hand over the investigation to the NIA because we feel that some kind of Jehadi activity was going on there. The CID is neither equipped nor will it be allowed by the TMC government to investigate the matter freely, as the blast took place inside the TMC office," Ghosh told PTI.
The state BJP is also sending a party delegation to visit the area tomorrow.
"During Khagragarh blast in Burdwan also we had said that jehadis were making bombs and it was proven later in an NIA investigation," Ghosh said.
On October 2, 2014, a blast had occurred in a house at Khagragarh in Burdwan town which claimed two lives. The NIA had later found that the two were Jamiat-ul-Mujahideen operatives from Bangladesh.