"Mountain of digital evidence" suggests Michigan high school shooting was planned, prosecutors say

Oxford High School Senior Austin Witt played football with 16-year-old Tate Myre—one of the four teenagers killed on Tuesday when a student opened fire. 14-year-old Hana St. Juliana, 17-year old Madisyn Baldwin, and 17-year-old Justin Shilling were also killed.  

Witt remembered Myre as always being happy. 

"Honestly, he was the heart and soul of our team and probably our community. He's a true hero, and my thoughts and prayers go out to his family,"  Witt tearfully told CBS News' Nancy Chen.