One personnel of the Manipur Rifles was killed and three injured in a bomb blast at Singjamei Super Market under Singjamei Police Station in Imphal this evening. Police sources said, some miscreants threw one hand grenade at the residence of one Executive Engineer of the state Irrigation and Flood Control Department in the area. All of them are escort guards of the Engineer.Security has been beefed up in the area after the incident and a search operation was going on.