Katherine Koonce (left) and a vigil at The Covenant School (right)
The Covenant School // John Amis/ AP
- Katherine Koonce was one of six who died in the mass shooting at Nashville's Covenant School Monday.
- Anna Caudill, Koonce's friend of 23 years, spoke to Insider about the school headmaster's legacy.
- Koonce was a 'mighty oak tree of a woman,' Caudill told Insider.
Katherine Koonce spent so much time advocating for the lives of her students — all while raising two children of her own ...