Complex sentence: On June 12,2016,49 people were killed and 53 others were wounded inside Pulse, a gay nightclub in Orlando, Florida, United States by a gunman before he himself was killed by police after a three-hour siege.
Split into simpler sentences: On June 12,2016, a mass shooting occurred inside Pulse, a gay nightclub in Orlando, Florida, United States, resulting in 49 deaths and 53 injuries. The gunman himself was then killed by police after a three-hour siege.