Around 250 crude bombs and materials used in making such explosives were seized from two plantations — mango and (an adjoining) bamboo — at Kaliachak in Malda on Wednesday night.

Police said also on Tuesday they seized 2,500-odd bottles of cough syrup — often consumed by drug abusers — from another mango plantation in the same area. They suspect that a section of smugglers and miscreants are using the mango plantations as their “stockyard” during winter as these plantations remain deserted during winter months.

Horticultural activities at the plantations commence in the spring season, said sources.

“Today (Wednesday) we found some suspected explosives, balls and other items used in making bombs. It seems that some people had made the explosives and stored them at the plantations,” said a police officer.

“As the plantations are near the India-Bangladesh border, we suspect that the illegal consignment (2,500 bottles of cough syrup) was stored there to be smuggled to the neighbouring country,” the officer added.

During the raid on Tuesday, the police arrested Harun Sheikh, a suspected member of a smuggling racket and also seized two stolen two-wheelers from the spot. “We are in search of three suspected smugglers, one from Habibpur and two from Kaliachak,” said a police officer.

Alok Rajoria, Malda police chief, said were on alert. “We request those living at the vicinity of these orchards to report if they notice any unusual activities at these orchards,” he added.