Rachel Cooper-Blackmore contributed to a memorial for Christina Green at their Tucson school.  As classes at Mesa Verde resumed for the first time since the shooting on Saturday that killed six people, including 9-year-old Christina, the school grappled with how to talk about the tragedy with the young students here. Many of them have never known anyone who has died. Now, one of their own had been killed — a loss that was difficult for many adults to deal with.  In the two nights since the shooting, nightmares had already interrupted sleep for many of the children — images of puppies suddenly dying, mothers crossing invisible lines and abruptly disappearing, or somebody coming to kidnap their friends in the middle of the day. The impact was raw and deep. Some children screamed and sobbed inconsolably, while others were stoic, promising their mothers that, yes, they understood, and, no, they did not need to talk.  They brought their stuffed owls and friendship bracelets and flowerpots as offerings for the growing memorial to Christina that lined the fence at the school. And her third-grade classmates hugged one another tightly in the yard before classes began.  “Are you sure you’re O.K.?” one asked a group of friends. “My mom said it’s O.K. to be sad.”  Kayley Clark, a classmate who had been friends with Christina for years, said, “I just feel shocked and very, very sad. She was very, very smart and very, very nice. She was such a fun person, and I really wish she could come back.”  Many students were already chattering about ways they could honor Christina. Could they name a local park in her memory? Or perhaps a baseball field, a tribute to the game she loved? Could they try to be more helpful to other students, as they had seen her do?  As parents escorted their children to class just after dawn, a few said they were worried about what their children would hear about the attacks, but many more said they felt a sense of relief that somebody else could help their children grieve.  And parents were mourning not only the death of a bright and popular young student, but also a sense of innocence for their children.  Tamara Clark, Kayley’s mother, said that when she told her daughter that Christina was the young girl killed on Saturday, she immediately burst into tears. Then, there was silence. Hours later came the anger “in a way I have never seen,” Ms. Clark said.  “She would say over and over that she hated the guy who did it,” Ms. Clark said. “ ‘Hate’ is a word I never really heard her use before.”  With fewer than 400 students at the school, nearly every child had at least seen Christina on the playground or at student council or with a tutoring program where she volunteered.  A team of psychologists arrived at the school early Monday, preparing to stay all week. Teachers began the day by telling students that the school was “like one big family, and we are all here to support each other in this time.” With that, students were encouraged to share memories of Christina in class.  “They told them it’s fine to be happy when you think about Christina and it’s fine to feel sad,” said Christine Parrish, whose 8- and 9-year-old daughters had known Christina for most of their lives.  School officials were trying to make the day stick to a normal schedule, although the circumstances were anything but.  “This is a multifaceted tragedy for this community,” said Vicki Balentine, the superintendent of the Amphitheater Public Schools district. “We want to give them space to do whatever we need to be supportive. And at the same time, we have to move forward.”  One class gathered in the schoolyard and held hands in a circle for the national moment of silence, as a car stereo blasted the sound of a single bell. The scheduled Family Library Night on Monday was replaced with a support gathering for families.  For many parents and more than a few students, there are the persistent thoughts of “what if?”  “There’s no reason we couldn’t have been there at that time, too,” said Betty Ordonez, whose granddaughter, Jordan Zepeda, is also in third grade at Mesa Verde. “That was the first thing I thought when I heard about it — where are my babies?”  Jordan said, “Now, I feel scared, just very scared.”  Ms. Balentine said the students seemed to be doing as well as could be expected, adding, “Children are remarkably resilient.”  Indeed, one of the most cogent messages (complete with misspellings) on the growing memorial came in a letter from Rachel Cooper-Blackmore, a fifth grader.  “Christina you will be missed by everyone,” it began, each “i” dotted with a heart. “I am so sorry for your family and I hope in their hearts you can guide them on the right pathway of live because yours was taken short.”
As classes resumed at Christina Green’s elementary school, officials encouraged her classmates, many of whom had starting having nightmares, to talk about their sorrow and fears.