Federal investigation agencies discovered important evidence about last week's suicide blast in Bunir and arrested six people on Wednesday, police said. The blast occurred during the by-election in NA-28 at a polling station on Sunday, killing at least 35 people. Investigators have recovered a shoe of the suicide bomber. They said the vehicle used in the blast was snatched from Karachi. They said 80 kilogrammes of explosive was used and hundreds of AK-47 bullets were packed in it to increase the intensity of the blast.