Two children and their father have been found dead in a house in Hinckley after reports of a disturbance.
Detectives said they believe the dead man found inside the property on Welwyn Road is David Stokes, 43, and that the two children were his sons, Adam, 11, and five-year-old Matthew.
Rachel Ayres the headteacher of St Mary's CE Primary School where the two boys attended said they have all been left "devastated by the tragic news" of the deaths of two young boys.
She added: "This is an extremely difficult time for our pupils, staff and parents and our priority is supporting them.
"Special assemblies are being held tomorrow to support the children. Prayers will be said and we will have staff and counsellors available to speak to the children to ensure we're providing as much help as we can during this traumatic time."
Officers said a woman called Sally Stokes who is the wife of David and the children's mother was also inside the house, and is currently being treated in hospital where she remains in a stable condition.
One neighbour, who did not wish to be named, said: "They were very nice people."
Leicestershire Police attended the address at around 9.30pm on Tuesday after calls from concerned residents, and contact was made with a man and woman in the property.
Negotiators and specialist officers were sent to the scene on Tuesday night, but when police gained access to the house a man was found dead in the property.
A search of the house also uncovered the bodies of two children, and a woman who was found with injuries was taken to hospital in the early hours of Wednesday morning.
Detectives said they are not looking for anyone else in connection with the incident, and that post-mortem examinations on the man and children are not due to take place before tomorrow.
A large section of the street was cordoned off by officers until Wednesday afternoon while investigations took place, and the property itself remains under cordon.
Many people living on the street appeared too distressed to talk to reporters about the incident.
Police officers continued to stand guard outside the semi-detached property in the Leicestershire market town into Wednesday evening.
Detective Chief Superintendent David Sandall, head of Leicestershire Police's crime and intelligence directorate, said: "A number of inquiries are now under way to understand what caused the three deaths, and the circumstances surrounding the events of last night in the house.
"Whilst we are not, at this stage, looking for anyone in connection with what happened, we would like to hear from anyone who may have information for us."
As officers had been in contact with the man and the woman, Leicestershire Police said the Independent Police Complaints Commission (IPCC) has been informed.
The police watchdog confirmed investigators have been sent to the "police post-incident procedure to assess the level, if any, of our involvement".