"They were the sweetest kids," Virginia Saldivar told NBC News. "Devy loved animals, Starbucks and thrift store shopping. She was my sunflower, my sunshine. Xavier was the sweetest boy. He loved anything Army and playing video games.
"Daisy was our princess. She was grandpa's girl. She loved kittens and dressing up, and watching YouTube videos. Dominic was my heart. He was the most amazing, loving boy. He loved playing his trombone, watching YouTube and playing video games. He loved his family and he would defend them against anything," Virginia Saldivar said in a statement.
"These kids lived across the street from us and we would see them everyday. They were our life."
Phil McCausland reported from Houston, and Tracy Connor reported from New York.
Tracy Connor is a senior writer for NBC News. She started this role in December, 2012. Connor is responsible for reporting and writing breaking news, features and enterprise stories for NBCNews.com. Connor joined NBC News from the New York Daily News, where she was a senior writer covering a broad range of news and supervising the health and immigration beats. Prior to that she was an assistant city editor who oversaw breaking news and the courts and entertainment beats.
Earlier, Connor was a staff writer at the New York Post, United Press International and Brooklyn Paper Publications.
Connor has won numerous awards from journalism organizations including the Deadline Club and the New York Press Club.
She lives in Brooklyn, N.Y.
Phil McCausland is an NBC News reporter focused on rural issues and the social safety net.