CBS News announced that Mike Wallace, star journalist and pioneer of the newsmagazine show 60 Minutes, died Saturday night. He was 93. Wallace was a tough interviewer who started on staff on the program when it began in 1968. He was known for spending hours preparing for interviews, tough follow-up questions, and ambush interviews with crooks. A CBS News correspondent said Wallace considered himself “nosy and insistent.” He retired in 2006, but did occasional interviews, including with Mitt Romney, Iran’s Mahmoud Ahmadinejad, and Roger Clemens.