A husband found dead with his headteacher wife and their seven-year-old daughter had spoken to police three days before allegedly killing them in a suspected double-murder suicide.
George Pattison, 39, was found dead with his wife Emma, 45, and their daughter Lettie at their home in the grounds of Epsom College in Surrey on Sunday.
Surrey Police confirmed that the deaths are being treated as a murder investigation.
The force said a firearm licensed to Mr Pattison was recovered from the scene, but cause of death would not be confirmed until post-mortems have been completed later this week.
Police said it had been in contact with Mr Pattison last Thursday after he notified officers of a change in address. The force has subsequently referred itself to the Independent Office for Police Conduct (IOPC).
The force added the firing range at the school did not form part of the crime scene and was not a line of inquiry in the investigation.
A police statement said: "We had contact with George on Thursday, February 2 after he notified us of a previous change of address, as is routine.
"Due to the short period of time between that contact and this incident, we have made a referral to the Independent Office for Police Conduct."
The IOPC said it is assessing the information available to decide if any further action is necessary.
Detective Chief Inspector Kimball Edey, senior investigating officer on the case, said: "This is an incredibly traumatic incident and we are working around the clock to investigate and understand the exact circumstances which led to this point.
"We understand the public concern and upset, and we will clarify what we can, when we can, while respecting the right to a level of privacy for the families of those who have lost their lives."
Mr Pattison had held a gun licence for a number of years and it was up for renewal early last year, according to the Times.
The newspaper said he had not been reported to Surrey Police before, but in 2016 had contacted them to allege that his wife had hit him, before withdrawing the claim.
The latest developments come after Emma's former colleagues paid tribute to their "dear friend", saying they are "immensely shocked and saddened" by the news of her death.
Speaking on behalf of Ms Pattison's former workplace Croydon High School, Cheryl Giovannoni said: "We are immensely shocked and saddened by the news about the death of Emma Pattison, her daughter Lettie and her husband George.
"Our thoughts are with their family at this time, as well as everyone at Croydon High School, and Epsom College, which Emma joined as head in September 2022.
"Emma was a much loved and respected member of the GDST community, as well as a talented head and teacher and a dear friend to many of us.
"She touched the lives of all of us with her energy, wisdom and kindness during her six years as head of Croydon High School and the school will always bear the legacy of her inspiring leadership.
"We are taking time to support staff and students at Croydon High School as well as everyone in the GDST family, and their wellbeing will be our priority in the coming days."
And nursery worker Chloe Rathbone, who previously took care of Lettie, said she was "utterly heartbroken" over the young child's death.
The 27-year-old told The Times: "I knew Emma, George and Lettie and I am utterly heartbroken over this news."
She added: "Lettie was perfect in every way."
Local MP Chris Grayling called the deaths "an appalling tragedy", adding: "I know everyone locally will be shocked about what has happened."
Epsom College said on Twitter that staff and pupils would pay their respects to their "wonderful head" Mrs Pattison.
The school said: "The shocking and tragic news has now reached many about the death of our head, Emma Pattison.
"The College community will be coming together today to process the news, grieve and pay our respects to a wonderful head.
"We will be in close contact with Surrey Police over the coming weeks and months.
"We hope everyone will respect the privacy of Emma's family at this time and allow the College's pupils, staff and wider community the time and space necessary to come to terms with this loss."
