Four passengers of an auto-rickshaw and its driver were killed when an unspecified vehicle hit the auto-rickshaw in Sanarpar bus stand area on the Dhaka-Chittagong highway in Siddhirganj upazila of Narayanganj early Wednesday.Identity if the deceased could not be known immediately.Sub-inspector of Siddhirganj Police Station Faridul Islam said the incident took place when an unspecified vehicle hit the Dhaka-bound CNG-run auto-rickshaw in the area at about 4:45 am, leaving four passengers of the auto-rickshaw and its driver dead on the spot.The bodies were kept in the police station.