Associated Press

ATLANTA — School-related killings occur most often just after students return from long summer or winter breaks, the U.S. Centers for Disease Control and Prevention reported Thursday.

"The start of each semester is a time of change and stress for students," said Dr. Mark Anderson, a CDC epidemiologist. "They have to adjust to new teachers, new classrooms, new schedules, new classmates. That could contribute to violent behavior."

The report found homicides decline steadily over the fall and spring semesters, bottoming out in December and June. Overall, there is roughly one school-related killing somewhere in America for every seven school days.

The report examined the 1992-93 through 1998-99 school years. It was timed for release as children prepare to return to class and designed to help schools plan anti-violence programs in the wake of heavily publicized school shootings.

A school-related homicide was defined as a killing that happened on campus, at an off-campus school function, or on the way to or from school. The CDC compiled the report from media accounts, confirming each death with local authorities.

The report did not specify who was responsible for the deaths.

February led the months of the school year, with about one homicide for every four days, followed by September with about one every six days. December had the lowest homicide rate — one for every 15 days.

School violence has fallen steadily over the past decade and remains extremely rare. Less than 1 percent of homicides and suicides of school-age children happen at school.

"There are many who believe that the time you could breathe easy is when school just begins, because there’s no time for students to get into trouble," said Bill Modzeleski, director of the Safe &Drug-Free Schools Program for the U.S. Education Department. "You just can’t let your guard down."

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