Police in St. Louis released new details Tuesday about the shooting at a high school that left a teacher and student dead and seven others injured.

Officials and family members identified the victims as 61-year-old Barbara Kuczka and 15-year-old Alexzandria Bell.

The 19-year-old gunman, who was killed by police within minutes of the first 911 call, used an AR-15-style weapon and had more than 600 rounds of ammunition during the shooting Monday at Central Visual and Performing Arts High School, Metropolitan Police Department Commissioner Mike Sack said at a press conference Tuesday. The gunman also left behind a handwritten  note, Sack said.

More than 100 people gathered at a vigil Monday night to honor the victims and share a range of emotions including “frustration, anger, grief,”  St. Louis Mayor Tishaura Jones said at the press conference.

“I know that tragic incidents like this traumatize our children, teachers and the larger community,” Jones said. “The scourge of gun violence that continues to plague the lives of our children and families in their communities is a national emergency. It’s a public health crisis that requires federal action.”

PREVIOUS REPORTS:2 killed, 7 injured in shooting at St. Louis high school

Who are the victims?

Eight people, including the gunman, were hospitalized. Kuczka died at a hospital;  Bell died at the school. The gunman also died at a hospital.

Andre Bell told St. Louis Post-Dispatch and KSDK-TV that his daughter, who was killed in the shooting, was a 10th grade student and a member of the school’s junior varsity dance team. Kuczka, who taught at Central for 14 years, was killed when the gunman burst into her classroom, Kuczka’s daughter Abigail told the Post-Dispatch.

Seven other people, including male and female students ages 15 and 16, were in stable condition and had injuries ranging from a broken ankle to shrapnel and gunshot wounds.

“This is a heartbreaking day for all of us,” Sack said.

Who was the gunman?

The assailant was identified as Orlando Harris, 19. He was fatally shot by police, officials said.

Harris graduated from the school last year and had no prior criminal history, Sack said. Harris had an AR-15-style rifle and what appeared to be more than 600 rounds of ammunition strapped to his chest, in a bag and dumped in stairwells, Sack said Tuesday. 

Investigators are trying to determine a motive. Sack said Harris left a handwritten note offering an explanation for the shooting and describing a life of isolation he called the “perfect storm for a mass shooter.”

How did the shooter get in the building?

Law enforcement officials provided few details about how the gunman got into the school, which Sack said has metal detectors and locked doors.

Sack said the gunman entered the building “in an aggressive, violent manner” with his firearm out. Sack declined to provide additional information Monday evening, citing safety concerns.

“You can understand that we want to try and make schools a hard target,” he said.