Complex sentence: Jack was thought dead once again after his car went off a bridge, but in June 2006, Jack and his amnesiac brother Steve, who everyone thought had died back in 1991, returned to Salem.
Split into simpler sentences: Jack was thought dead once again after his car went off a bridge. In June 2006, Jack and his amnesiac brother Steve, who everyone thought had died back in 1991, returned to Salem.