Police said a “combination of factors” apparently led to a 15-year-old student committing an act School shooting at a private Christian school in Madison, Wisconsin, but declined to provide further information.

The shooting at Abundant Life Christian School left three people dead, including the perpetrator, whom police have identified as a student Natalie Rupnow. Rupnow, who also went by Samantha, appears to have died of a self-inflicted gunshot wound, police said. The other two dead were a teacher and a teenage student, whom police have not identified. Six people – a teacher and five students – were injured. Four remain in hospital.

In a news conference Tuesday afternoon, Madison Police Chief Shon F. Barnes said he would not provide further details about Rupnow’s motive to avoid jeopardizing the investigation. He asked anyone with information about Rupnow’s mental state before the shooting to contact Madison CrimeStoppers.

Barnes said investigators are looking into Rupnow’s social media presence, but did not share specific information about the teen’s behavior online. Investigators are also trying to determine whether Rupnow was bullied and whether that influenced her actions, Barnes said, but did not say whether anyone was targeted.

“Everyone was targeted in this incident,” Barnes said. “Everyone was equally at risk.”

Police are investigating how Rupnow obtained a gun, Barnes said Monday, and Rupnow’s family is cooperating with the investigation.

Barnes also addressed the distribution of a document allegedly related to the shooting that was circulating online. Barnes said that the authenticity of the document cannot be verified and that investigators were working on the origins of this document and how it came to be shared online. He asked that the document not be further distributed or shared and said police would provide an update where possible.

Barnes also clarified an earlier statement that a second-grader reported the shooting to 911. He said the shooting was actually reported by a second-grade teacher.

Barnes and other local officials said there have been multiple threats of strikes against local schools, leading to suspensions. None of these threats resulted in violence.

A vigil honoring the victims of the shooting will be held Tuesday at 6 p.m. local time at the Capitol building in Madison, said Mayor Satya Rhodes-Conway.