A worker from a builder's merchant is believed to have shot dead his wife and daughter near a swimming pool in a small market town.
The horror unfolded near Castle Swimming Pool in Spalding, Lincolnshire, when Lance Hart, 57, killed partner Claire, 50, and 19-year-old daughter Charlotte with a shotgun, before turning the weapon on himself.
Officers and paramedics battled to save the two women who they found gravely injured at around 9am on Tuesday. Mr Hart was already dead, and no shots were fired by police.
Investigators raided the family home in Hatt Close, Moulton, where one neighbour described Mr Hart as "always caring" and a "very nice guy."
The resident, who gave his name as Peter, said: "Lance worked as a delivery driver for a builders' merchants - we've had quite a bit of stuff from them - but he was always caring and would come around afterwards to see whether we could carry stuff.
"Last time I spoke to him, he had put the house on the market because they were hoping to downsize, buy somewhere in the village. He was a very nice guy, he went out of his way to be helpful so it comes as a great shock.
"He was full of the joys of spring. His kids had left home and they were going to downsize and find a bungalow in the village."
The local community reacted with shock. A resident of Pinchbeck Road, near the swimming pool, said she was "terrified" when she heard the news.
District councillor Gary Taylor, who represents Spalding Castle ward, said: "It's terrible news and local people are very shocked. It's a very quiet place, gun crime does not exist in this area at all. It's shocking news."
Witnesses reported hearing "dozens" of police cars and an air ambulance heading to the scene.
Speaking to journalists outside Spalding police station, Temporary Superintendent Paul Timmins said officers found a dead man and two gravely injured women when they were called to the scene at around 9am.
He said: "CPR was attempted on both women and I am sad to report that both women have died. We believe a shotgun was involved in the incident and are currently investigating the circumstances of this tragic incident.
"We confirm that we are not seeking anyone else in connection with this tragedy. I can also confirm that no shots were fired by police and that this is not being treated as a terrorist incident.
"Clearly, a situation such as this for a small community like Spalding is hard to comprehend. We are working alongside colleagues from the East Midlands Major Crime Team in order to provide answers around what has happened today."
East Midlands Ambulance Service said paramedics were told to approach the scene with caution and fought to save the three people who died.
A spokeswoman said: "Despite the best efforts of everyone at the scene, the patients were pronounced dead. This is a tragic incident and our thoughts are with the friends and families of those involved."
Labour leader Jeremy Corbyn said on Twitter: "Shocking events in Spalding, Lincolnshire. My thoughts are with the victims and their families."
Lincolnshire Police, South Holland District Council and the British Red Cross are giving support to anyone affected by the shooting.
Witnesses and anyone with information is urged to contact police on 101, quoting incident number 92 of Tuesday.