The bodies of Lucy Carter, seven, her sister Hollie, three, and brother Thomas, four, were found yesterday in a car in a remote beauty spot near the Alton Towers theme park.
Their father, Steven, 36, was discovered hanging from a tree 200 yards away.
Residents in the hamlet of The Blythe, near Uttoxeter, were stunned by the tragedy. Pub landlord Barry Edwards said Mr Carter - who was unemployed - was a "dedicated father", who would often visit with his children.
He said: "He seemed like an extremely caring father and would sit and watch his kids play on the swings in the pub garden. He would buy them orange juice but never allow them to have fizzy pop."
Mr Edwards described the children as being "full of beans" and said their father was a popular regular, who showed no signs of being unhappy.
Neighbour Jonathan Rigby said: "We live in a tiny community where everybody knows everybody else, so this has left everyone devastated. The children were very friendly little things and I can't believe they're gone."
The children were discovered by a farm worker in their father's black Ford Capri at 10am yesterday.
The farm worker said: "The two girls were just huddled up together in the back of the car and the boy was lifeless in the front. This was a terrible sight and one which I shall never forget."
Police said a small fire had been lit in the car but tests were still continuing to establish the exact cause of the children's deaths.
Detective Superintendent Jeff Virgo said police were treating the youngsters' deaths as unlawful but were not seeking anybody else in connection with the incident.
Their mother, Teresa, 32, was said to be "utterly devastated" and was today being comforted by police.
Det Supt Virgo said it was believed the couple had suffered domestic problems in the weeks leading up to the tragedy.
One neighbour, who did not wish to be named, said the couple had split up in recent months but were trying to resolve their differences.
A briefcase belonging to Mr Carter was discovered in the back of the car. Inside were family photographs, financial documents and letters.
Det Supt Virgo said the Carters were not known to Social Services as a problem family and the children were not on an at-risk register.
The youngsters had shown signs of having been affected by the heat of the fire lit in the vehicle, but it was not yet known whether they had succumbed to toxic fumes, he said.
Police said the car's lights were on when officers arrived at the scene, suggesting the father and his children may have travelled to the beauty spot at night.
"We are trying desperately to piece together exactly why this tragedy has occurred," Det Supt Virgo said.
"There's a suggestion there was domestic strife within the family and this will form part of our investigation."
He said the children's mother last saw them on Saturday morning before going to work at a dry cleaners in Stafford.Reuse content