An on duty police officer died while 13 persons, including a child, were injured when a swing fell down at Surajkund fair here on Saturday, just an hour after two persons, including a child, got hurt in a gate collapse incident, officials said.District Deputy Commissioner (DC) Ayush Sinha and MD Tourism Parth Gupta reached the scene immediately after receiving information.Arrangements were immediately made for the treatment of the injured persons, he added.According to the police, around 6 pm approximately 15 persons were on the swing when it suddenly collapsed.Rescue operations were immediately launched to help the injured. During the rescue operation, a stall operator, Raghav, was also struck by a swing grill, injuring his shoulder.Earlier, around 5 pm, gate number 2 of the fairgrounds suddenly collapsed, injuring two people, including a child.