Complex sentence: Before and during the trial, Thompson and Bywaters were the subjects of a highly sensationalist and critical media commentary, but after they were sentenced to death, there was a dramatic shift in public attitudes and in the media coverage.
Split into simpler sentences: Before and during the trial, Thompson and Bywaters were the subjects of highly sensationalist and critical media commentary. However, after they had been sentenced to death there was a dramatic shift in public attitudes and in the media coverage.