Two unidentified motorbike riders were killed when an over speeded truck on Monday knocked them down in Site area of the provincial capital. According to police officials, the accident took place near Habib Bank branch in Site area when a recklessly driven speedy truck hit the two motorcycle riders leaving them critically injured. The driver of the truck managed to escape from the scene after the accident. The injured were shifted to Abbasi Hospital but both succumbed to their injuries. The deceased have not been identified as yet. Police had registered a case and initiated probe against unknown driver who had escaped from the spot.