There are many schools in the United States that have been the target of school shootings in the past, and now some of them are starting to see more of them.
The Boston Marathon, a venue that has been a focus of school-related violence in the last several years, saw four shootings last month, two of them of students.
The incidents took place at Harvard Medical School and in the schools of Northeastern University, Boston University and the University of Massachusetts Boston.
The shootings were also at the University at Albany, University of California, Berkeley, the University University of Virginia, Yale University and Northeastern State University.
The University of Wisconsin at Madison was the site of a school-area shooting in April 2016.
In October 2016, an armed student in Florida was charged with opening fire on a school of students at Florida International University.
There have also been two school shootings involving guns in Pennsylvania, the state capital.
In July 2017, three people were killed and 14 wounded in a shooting at a school in Kansas City, Missouri.
Last year, a gunman shot and killed three people at a Colorado high school.
In the case of the Massachusetts school shooting, two students were killed in a separate incident in September 2016.
That incident happened at the end of a baseball practice, and the third student was wounded by the gunman who later died at the scene.
A shooting in the US Capitol in Washington, DC, in June 2018 killed nine people and injured dozens more.
In August, three women were shot and injured in a home in Dallas.
The two women were identified as Brittany Maynard, 21, and Ashley Jackson, 25.