(CNN) -- Friends of Claire Davis, the 17-year-old senior critically wounded in Friday's shooting at a Colorado high school, are wondering why bad things happen to good people, yet are thankful she made it through the night.
Davis is in a struggle for her life at a hospital in Littleton, near Arapahoe High School, where a classmate shot her in the head.
Police say the gunman was looking for revenge against a librarian, but couldn't find the faculty member and killed himself as a school resource officer closed in.
Davis was just a random victim, police surmised, and the gunman and victim didn't even know each other.
Davis' classmates spoke well of her. They used words like spunky and bright.
"She was just a very sweet girl. She's really smart," August Clary told CNN affiliate KUSA. He said Davis loves to ride horses and "wouldn't hurt a fly."
Davis' family released a statement through the sheriff's department.
It said, in part: "Our beautiful daughter, Claire Davis, has severe head trauma, as the result of a gunshot. She needs your continued prayers. We would like to thank our family, friends, the community and the equestrian community for their outpouring of love and support, as well as the school for their continued support of the students and teachers."
Hundreds of people attended a vigil for Davis on Saturday night.
Katie Snively, a senior at Arapahoe, said it was important to honor and pray for Claire.
Many people were tweeting to the hashtag #prayforclaire.
"Claire is a hero. our hero. she deserves to be rewarded not only with thanks, but with another chance at life," Aidan Loughran wrote.
"Thank God for waking us up again and for keeping Claire through the night. Don't forget to pray as we wake up this morning," Jonathon Bailey tweeted Sunday.
Davis' father told CNN affiliate KMGH late Saturday that his daughter is "not doing very well." The station said doctors are worried about swelling to her brain, according to a family friend.
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