WISCONSIN (Reuters) -- A 15-year-old girl opened fire in a Wisconsin school classroom on Monday, fatally shooting a fellow student and a teacher and wounding six other people before killing herself with the handgun, police said.
The shooting took place in a mixed-grade study hall shortly before 11 a.m. (1700 GMT) at the Abundant Life Christian School, which has 420 students from pre-kindergarten through 12th grade.
The shooter was a student at the school, identified by police as Natalie Rupnow, who also went by the name Samantha.
A second-grade student, who would generally be 7 or 8 years old, called 911 to report the shooting at the school, Madison Police Chief Shon Barnes told a press conference.
“Let that soak in for a minute,” Barnes said.
The two shot dead were a teenage student and a teacher, Barnes said without identifying the victims.
Two wounded students were in critical condition with life-threatening injuries, while another teacher and three other students were wounded and expected to survive.
School shootings have been a macabre routine in the United States, with 322 of them this year, according to the K-12 School Shooting Database website. That is the second highest total of any year since 1966, according to that database - topped only by last year’s total of 349 such shootings.
Monday’s rampage was a rarity in that it was carried about by a girl. Only about 3% of all U.S. mass shootings perpetrated by females, studies show.
There was as yet no known motive for the violence.
Asked how she got the gun, Barnes said, “Good question. How does any 15-year-old get ahold of a gun?”
At a previous press conference, Barnes lamented how the tragedy would affect Madison, the capital of Wisconsin with a population of about 270,000.
“Every child, every person in that building, is a victim, and will be a victim forever. These types of trauma don’t just go away,” Barnes said.
Gun control and school safety have become major political and social issues in the U.S. where the number of school shootings has jumped in recent years.
The gun violence epidemic has afflicted public and private schools alike in urban, suburban and rural communities.
 The Wisconsin shooting took place 12 years and two days after one of the most notorious school shootings in U.S. history: the massacre at Sandy Hook Elementary School in Newtown, Connecticut. A 20-year-old man armed with a semi-automatic rifle killed 20 school children plus six adults who worked at the school.