Friends and family have paid tribute to the three young children found dead at a beauty spot near Shrewsbury.
Sam Fuller, 12, and his sisters Becka, eight, and seven-year-old Charlotte, who was known as Charlie, were described as "absolutely delightful children" by teachers.
Officers found the bodies of the three siblings in an isolated area of woodland near Pontesbury, Shropshire, shortly before 10am yesterday.
On Monday night Police said the deaths were down to a "tragic family situation". They have launched a murder investigation but are not looking for anyone else in relation to the tragedy.
Their father, university graduate Ceri Fuller, 35, was also found dead nearby.
It was reported that the children had suffered knife wounds while Fuller had fallen from a cliff at a nearby quarry.
Fuller and his three children had left their home at Milkwall, near Coleford, Gloucestershire, last Thursday.
Police later appealed for sightings of the four and said they were believed to have been travelling in an 11-year-old red Land Rover Freelander.
Becka and Charlie were pupils at St John's Church of England Primary School in Coleford, which older brother Sam had also attended before moving to secondary school.
Headteacher Jan Wagstaff said: "Rebecca and Charlotte were absolutely delightful children and a pleasure to have in school.
"Sam was also a pupil here before he moved on to Lakers. He was a lot of fun and always had a ready smile. They will all be very sadly missed.
"Our thoughts and prayers are with their family."
Alison Elliott, head of Lakers School in Coleford, added: "We are desperately sad to hear the family are having to face such a dreadful situation.
"Sam was a well loved member of our extended family here at Lakers. Our thoughts are with the family at this very tragic time.
"We have arrangements in place to support students, staff, friends and family at this very difficult time."
Fuller married his wife Ruth in August 2009 and neighbours said they had lived in a cream pebbledash semi-detached home on Station Road in the village of Milkwall for about a year.
Neighbours said the family "kept themselves to themselves" but spoke of their shock.
Janice Ayres, who lives next door to the Fuller family, said: "Very, very sad, I just cannot say any more.
"I didn't even know her name (mother of children). I have children of my own and I would just be devastated.
"I am surprised. They kept themselves to themselves.
"It's so sad for three young children.
"Being out at work all day you don't really know your neighbours. We would speak if we saw each other in the garden but we never socialised together.
"They were no trouble at all. They've lived here about a year and as far I know they bought the house as we knew the man who lived there before and he was selling it.
"It is dreadful really to think about it. It's the way life is these days.
"You just live your own life."
Another neighbour, who did not wish to give their name, added: "They hadn't lived here all that long. They kept themselves to themselves."
Rachel Annis, whose daughter went to the same school as Charlotte, told 5 News: "Charlotte was in my daughter's class at St John's. She was just a beautiful little girl. (They were) such characters.
"Sam would often come round and play with my son and so would Charlotte who was in my daughter's class.
"She just had an angelic face, such a little angel."
Mrs Fuller's father, Ron Tocknell, from Lydney, Gloucestershire, appealed for information when his son-in-law and grandchildren disappeared.
He wrote on his Facebook page: "If anyone who knows Ceri has any idea of his whereabouts, please contact Glos. police immediately. We are all so worried."
Fuller worked as a production supervisor at the Lydney-based Glatfelter paper mill, having joined in 2002.
According to his LinkedIn profile, he was educated at Whitecross School in Lydney before taking A-levels in physics, chemistry, biology and general studies at the Royal Forest of Dean College.
He then completed a BSc in molecular and cellular biology at the University of Huddersfield, graduating in 2001.
A spokesman for Gloucestershire Police said: "Officers searching for missing man Ceri Fuller and his three children, from the Forest of Dean, have been made aware of the discovery of four bodies in Pontesbury, Shropshire.
"While the bodies have yet to be formally identified, Mr Fuller's family have been informed of the discovery and are being supported by police family liaison officers.
"The investigation into the deaths is being conducted by West Mercia Police." West Mercia Police said: "West Mercia Police are investigating the deaths of an adult and three children after the discovery of four bodies in the Pontesbury area.
"The deputy coroner for Shropshire, Andrew Barkley, has been informed and officers have sealed off the area. Forensic examinations of the area will take place in due course."
Last night Det Chief Insp Neil Jamieson of West Mercia Police said the registration number of the red Land Rover Freelander was CK51 YUV.
Speaking at a press conference at Shrewsbury Police Station, he said police believe the vehicle left Gloucestershire last Wednesday night or early Thursday morning and is thought to have been seen in the Leominster area at midday on Thursday before being driven up to the Welshpool area later that afternoon.
On Monday morning a member of the public reported it was parked at the entrance to Poles Coppice, about 300 yards from where the bodies were found.
He urged anyone who had seen the car or its occupants to call West Mercia Police on 101. He put the deaths down to a "tragic family situation".
Reverend Alan Wearmouth, chairman of governors at St John's Church of England Primary School, told of the moment the tragic news was broken to Becka and Charlie's school friends.
Talking to ITV's Daybreak, he said: "When the head got the news she took some advice and discussed it with one or two people and then called an assembly for the children.
"All the children came in and the head, remarkably calmly and professionally, informed the children that sadly their friends' bodies had been found and that they were dead and would not be returning to school.
"We then had a moment of silence, said a prayer, lit two candles for them and the children went back with their teachers or stayed in the hall as was appropriate."
Wearmouth said he did not think people in the local community would respond to the children's deaths by "going down the road of anger and hatred".
"They will support each other in helping themselves through this," he added.
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Gloucestershire Police undated handout photo of Ceri Fuller. Three children who were reported missing with their father have been found dead, sources said.