The justices declined, without comment, to hear an appeal of a ruling that kept families from placing at the school tiles they made that had references to God.
Brian Rohrbough, whose son Danny was killed, said the district had no business telling him what he could say in two 4-inch tiles, among 4,000 placed above school lockers along corridors.
"If you asked me to create a memory of my son, it is always going to include a reference to God, because it is a core value," said Rohrbough, adding that the tile was not meant to proselytize.
Rick Kaufman, spokesman for the Jefferson County School District, said it had done what was best for the school and students to avoid dwelling on the killings. He said other memorials were established outside the school.