Florida Senator Marco Rubio appears via video to those in the arena. It receives a subdued response.
However, Texas Senator Ted Cruz walks out immediately afterward to huge cheers from the crowd.
Cruz congratulates Trump on winning the presidential nomination at the convention the night before. He says he wants to see the principals of the party prevail in November.
Cruz tells the story of a Texas family whose husband and father, a police officer, died in the recent mass shooting in that city.