The head of Epsom College has been found dead along with her husband and seven-year-old daughter in a property on school grounds.
Emma Pattison, 45, her husband George, 39, and their daughter Lettie, seven, were found dead at 01:10 GMT on Sunday.
Surrey Police said they were called to the property by South East Coast Ambulance Service.
Police said they were confident it was an isolated incident "with no third-party involvement".
An investigation is being carried out to establish the circumstances of their deaths.
Detective Chief Inspector Kimball Edey said: "On behalf of Surrey Police, my team, and I, I first want to express my sincerest condolences to the friends and family of Emma, Lettie and George, as well as to the students and staff of Epsom College, for their tragic loss.
"I want to give my assurance that we will conduct a thorough investigation into what took place last night, and hope to be able to bring some peace in these traumatic circumstances. I would ask that their privacy is respected at this very difficult time."
Ms Pattison became Epsom's first female head in September 2022 after six years as headteacher of Croydon High School in south London.
Boarding students at the college pay more than £42,000 a year, and its alumni include Conservative MP Sir Michael Fallon, broadcaster Jeremy Vine and comedian Tim Vine.
The head teacher's husband George was a chartered accountant who was director of a management consultancy firm called Tanglewood 2016, according to Companies House.
The chair of the board of governors at the school called his late colleague "a wonderful teacher, but most of all, a delightful person".
"On behalf of everyone at Epsom College, I want to convey our utter shock and disbelief at this tragic news," Dr Alastair Wells said.
"Our immediate thoughts and condolences are with Emma's family, friends and loved ones, and to the many pupils and colleagues whose lives she enriched throughout her distinguished career."
Sheena's daughter attends Croydon High School, where Ms Pattison previously worked.
The parent, who only wished to give her first name, said the news was "an utter shock and tragedy".
She told BBC News: "In her time as head teacher, she turned the school around, and she did so many things that enriched the children's lives.
"She was slight but very formidable, she knew all of the pupils by name. She was exactly what you would want from a head teacher."
Inspector Jon Vale, Epsom and Ewell's borough commander, said: "We're aware that this tragic incident will have caused concern and upset in the local community.
"While this is believed to be an isolated incident, in the coming days our local officers will remain in the area to offer reassurance to students, parents, teachers and the local community.
"I would like to thank the school and the community for their understanding and patience while the investigation continues."
Surrey Police added that the three deaths have been reported to the coroner.