The members of Rapid Action Battalion (RAB) detained an alleged illegal arms trader from Shibganj upazila in Chapainawabganj district on Sunday morning.The detainee is Alauddin, 50, who hailed from Ghorapashia village in the upazila.Eight pistols, sixteen magazines and 140 rounds of bullets have seized from his possession.Major Ahsan, RAB-5 camp in charge in the district confirmed the matter.