Jennifer Berger told ABC News she and Ritzer were best friends for nearly their entire lives and she was always destined to be a teacher.
"I remember when we were in kindergarten she brought in her little sister for show-and-tell. She always loved working with kids. I think they just gravitated towards her and I think as much as they loved her she loved them a hundred times more," Berger said.
Ritzer is the second teacher allegedly killed by a student in the U.S. this week. A Sparks, Nev., middle school teacher was allegedly shot by a 12-year-old student Monday.
With reporting by ABC News' Anthony Castellano and Phil Dean.