According to DSP Purna Chandra Joshi at Siraha police office, they seized an automatic pistol and two homemade pistols from three of them.
They have been identified as Rabindra Kumar Mandal, of Bhagwanpur 3, Dipendra Kumar Mahato of Dhangadhi-4 and Mahesh Kumar Yadav of Bastipur-1 of the district.
Police said that investigation is underway to examine the involvement other four people in the illegal activities.
According to police, the arrestees had been gathering in and around the highway areas with motive to looting motorbikes and abduction.
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