Michigan mass shooter Ethan Crumbley pleaded guilty Monday to a slew of murder and terrorism charges for slaughtering four classmates at his Detroit area high school when he was just 15. The disturbed teen, now 16, pleaded guilty to a total of 24 charges over the carnage nearly a year ago at Oxford High School that also wounded six other pupils and a teacher. He withdrew his intent to pursue an insanity defense, instead admitting the first-degree murders of classmates Madisyn Baldwin, Tate Myre, Hana St. Juliana and Justin Shilling last Nov. 30. Asked by Judge Kwame Rowe if he...