Complex sentence: His killer was believed to be a former member of the same company, known for his strong republican views, who resigned from the UDR after just one year, and who moved to the Republic of Ireland after the shooting and never came back.
Split into simpler sentences: His killer was believed to be a former member of the same company, known for his strong republican views, who resigned from the UDR after just one year. He moved to the Republic of Ireland after the shooting and never came back.