His friends said he didn't have any enemies. Rubin was a valedictorian at Christ Lutheran High School in 2003. People who knew him said he had a big impact on their lives there.
"Surreal doesn't even cover it," said Sandy Spitz, who was one of Rubin's high school teachers. "Unreal is more how we are looking at this."
Spitz said he was a serious student who always did his best work.
"He built a trestle bridge out of Manila file folders and he had plans and designs for that and he carefully worked on that for an entire semester," said Spitz.
Students and teachers feel like family at this small school. Spitz said she was surprised when quiet Rubin took a role as the villain in the senior play.
"He was fantastic," said Spitz. "He just blew us all away. We had no idea because he was so quiet. We had no idea he would be so outspoken on the stage."
He was well-liked among his classmates. Spitz said that makes this weekend's events even more unbelievable.
"You never think something like that is going to happen and when it does, it's just shocking," said Spitz. "Our prayers go out to his family for comfort and peace."
Investigators have been very quiet about the case. They aren't releasing any new information at this time, so there's no word on any leads or suspects in the shooting.