Police say it appears the motive in a shooting that left two dead, along with the suspect, at a private school in Wisconsin was due to “a combination of factors”.

Madison Police Chief Shon Barnes did not provide specifics as to what allegedly led a 15-year-old girl, Natalie Rupnow, to fire shots in a classroom at the Abundant Life Christian School in the city of Madison.

Six people were also injured in Monday’s attack. Rupnow died from a self-inflicted gunshot wound.

Chief Barnes said that investigators are asking anyone who knew the suspect to come forward with information.

“Identifying a motive is our top priority,” he told a press conference on Tuesday. “But at this time it appears that the motive was a combination of factors.”

“We are asking anyone who knew her or who may have insights into her feelings leading up to yesterday to please contact the Madison-area Crime Stoppers.”

Rupnow’s family has been co-operating with the investigation, said officials. Local media reported that a property north of Madison was raided after the shooting.

The teenager, who also used the name Samantha, split time throughout her childhood between the homes of her parents, who were separated, CBS News, the BBC’s US partner, said, citing court documents outlining the custody agreements.

Rupnow’s father posted a picture on Facebook of his daughter at a shooting range earlier this year, US media reported, saying they had joined a local gun club. “We have been loving… every second of it!” he reportedly posted.

His Facebook page includes a picture of what appears to be his daughter aiming a gun at clay pigeons in a field, wearing a T-shirt from the band KMFDM, a German group whose lyrics were posted online by one of the two teenage attackers in the 1999 Columbine school shooting.

KMFDM condemned that massacre at the time, according to Reuters.

It remains unclear who owned the gun used in the attack and where the weapon originated.

Chief Barnes told the Associated Press the suspect had two handguns but only used one in the attack.

Police are looking into the suspect’s social media as part of the investigation.

Chief Barnes said investigators are also talking to students at Abundant Life Christian School to understand whether bullying could have been a factor.

The condition of the injured victims had not changed since Monday night. Two were in hospital in a life-threatening condition. Two were stable. Two others had been discharged.

Emergency radio transmissions indicate five of the injured victims taken to Madison hospitals were around 14 to 17 years old and that two were boys and three were girls, according to the Milwaukee Sentinel Journal.

The two victims shot dead were a teenage pupil and a teacher. None of the victims have been named by authorities but an online obituary identified the student as Rubi Patricia Vergara, 14.

“She was an avid reader, loved art, singing and playing keyboard in the family worship band,” it read.

The teacher was identified as 42-year-old Erin West by the Dane County Medical Examiner, CBS News, the BBC’s US partner, reported.

Madison Mayor Satya Rhodes-Conway said on Tuesday that officials will share information when they can.

“It is absolutely none of ya’lls business who was harmed in this incident,” she said during a heated exchange following a reporter’s question during the press conference.

“Please, have some human decency and respect for the people who lost loved ones or were injured themselves or whose children were injured.”

Chief Barnes on Tuesday also clarified that a 911 call reporting the shooting came from a second-grade teacher and not a second-grade student, as was previously stated.

He apologised for the error and said he misread a police log about the incident.

He also said that there were numerous schools in the area that had been targeted by hoax threats, known as swatting, on Tuesday morning. Police do not believe there are any current threats to those campuses.

“As a community, we must not allow violence or any act of violence to define us,” he said.

“We refuse to allow hate, destruction to win in this city, but rather we will honour our survivors, our victims, through love and support in the Madison way.”