DENVER — Leia Pierce shuffled out the front door on Tuesday. Her son, Jamel Myles, 9, had killed himself last week, and she was still struggling with the basics. Eating. Sleeping. “I took a shower, but I put the same clothes back on,” she said, staring at the ground. “I need him back.”

Jamel, a fourth grader at Joe Shoemaker Elementary School in Denver, hanged himself in his bedroom last Thursday, according to the county coroner, and his death has plunged a mother into despair and a community into disbelief.

Ms. Pierce says her son committed suicide after a year in which he and his older sister were bullied frequently at school. Over the summer, he had told his mother he was gay. Now, she is angry at the school, which she believes should have done more to stop the taunts and insults.

Will Jones, a spokesman for Denver Public Schools, said administrators planned to conduct a thorough review of the case. “We are deeply committed to our students’ well-being,” he said in a statement.