Police have confirmed three people were killed and another three were injured in connected attacks in Nottingham on Tuesday morning (13 June).A man was later arrested in connection with the incidents, which have seen a number of roads closed across the city.Two 19-year-old students from the University of Nottingham, and a man in his 50s, were stabbed to death. Police believe the older victim's van was stolen and driven at three other people, with one left critically ill.Here is what we know about the incidents so far.