At a Monday press conference, Antigo, Wisconsin, Police Chief Eric Roller said the shooter, Jakob Wagner, arrived to the school on a bicycle. At around 11 p.m., he began firing a rifle on the grounds of Antigo High School, where the prom was taking place.
A student and his date who were attending the prom were non-fatally shot as they left the school, say police.
Officers who were patrolling the parking area heard shots fired and acted immediately, according to a statement released Monday. "One of those officers was able to fire upon the shooter, stopping the threat to additional attendees," the statement said.
"We stopped the threat and we think it saved many lives," Roller said at a press conference on Monday, adding that the shooter was stopped in the parking lot before entering the school building, which police believe he intended to do.
In a statement, Roller said, "The prior and ongoing training that our officers receive was truly imperative in preventing additional injury and casualties during this incident. Our departments will continue to provide the utmost security and safety measures to our community."
Police: No Known Motive for ShooterBased on their initial investigation, which included executing a warrant at his home, police believe Wagner acted alone. Roller said Monday he does not know where he acquired the gun.
While a police source says authorities do not know his motive, a former classmate told the Wassau Daily Herald that Wagner was "bullied a lot."
"Ever since we were younger, he was one of the kids you kind of watched out for," 19-year-old Emily Fisher told the newspaper. "If someone was going to shoot the school, we thought it was going to be him."
Fisher told the paper Wagner was bulled in middle school and high school. She added that he talked about guns and weapons and made models of them in art class.
Childs described Wagner as "a sometime student." Administrators reportedly said he did not graduate with his class in 2015 and was working on earning his high school diploma.
Roller said in a statement that the Antigo Police Department is being assisted by the Wisconsin Department of Justice Division of Criminal Investigation.
Roller also expressed his "deepest sympathy to the attendees who had their prom night memories turn to fear and tragedy. I understand the concern and frustration of the families who were unsure of the situation and worried about their children. Officers and I appreciate the patience that was displayed by students and their families as our staff was able to secure the facility and ensure the safe removal of students."
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Victim Shot in Leg 'Doing Well,' Says FamilyDonald Childs, an administrator with the Unified School District of Antigo, tells PEOPLE that the male victim was a student at the school who underwent surgery on his leg Sunday morning for non-life-threatening injuries. According to Roller, students tied a necktie around his leg as a tourniquet.
The female victim was his date, from out of state, and was grazed in the shooting, Child says. She was treated for one gunshot wound and released, according to the statement.
The male victim's family, who asked to remain anonymous, released a statement Monday about the shooting, asking for prayers for the victims and the shooter.
Saying that the victim is "doing well," the statement adds: "He has come through a long surgery and will recover with time and effort, but we have always believe that God is good and has a plan even in the midst of tragedy."
Saying they are grateful to police and to hospital staff, the family added, "We are so thankful for his girlfriend and two friends on the scene who acted so bravely and calmly."
While asking for prayers for their son and his girlfriend, the family also asked people to pray for Wagner, who died at 1:06 a.m. Sunday at a nearby hospital "after lifesaving measures" were performed, said police.
"Please also pray for the family of Jakob Wagner," the statement said. "As much as we are struggling through this event, we cannot imagine the grief they are experiencing at this time."
An autopsy of Wagner's body has been conducted and results are pending," Roller said in his statement Monday. "My sincerest condolences to his family and friends as they mourn the loss of a beloved member of their lives."
The school district provided counseling to students returning to school Monday, according to a statement from the district obtained by PEOPLE.
"The district is following the advice of law enforcement experts in conducting school on Monday and providing structure and routine as best we can and as quickly as we can," the statement said. "Counselors at each school site are prepared to support any students or staff who may be struggling."