Complex sentence: In 1945, the Red Army occupied the town and put it under Polish administration.A dangerlously low flight was performed by a Polish Su-22 in the town on 6 August 2012, this incident is under investigation.
Split into simpler sentences: In 1945, the Red Army occupied the town and put it under Polish administration. A dangerously low flight was performed by a Polish Su-22 in the town on 6 August 2012; this incident is under investigation.