A retired 84-year-old teacher who was found stabbed to death in her home has been described as a "lovely lady" and "everybody's grandma" as police linked her murder to the stabbing of a nine-year-old boy and another incident involving a child.
A 26-year-old man is being questioned by police about the death of Louisa Denby, who was found with multiple stab wounds at her home in Shipley, West Yorkshire, as well as the attack on the school boy and another incident in which an eight-year-old girl was chased through a garden, forcing her take refuge in her house.
The discovery of Mrs Denby's body in the bedroom of her semi-detached house in Prospect Mount came just hours after the boy was airlifted to hospital from the Carnegie skate park, about 300m away, with chest and arms injuries.
Witnesses described how the youngster was stabbed in an apparently random attack and was covered in blood.
Detectives said there appears to be no connection between the injured boy and Mrs Denby and the attack in the park came without warning and for no reason.
Lisa Lacey said her 18-year-old son, Eli, saw the boy being stabbed and chased his attacker.
Describing the incidents as "a nightmare", the grandmother said: "My son was in the park. A little lad, nine years old, came running up to him saying, 'Eli, I've been stabbed'.
"He was holding his hand and blood was pouring out all over.
"Eli saw the lad so he set chase, chased him over Carr Lane way but lost him because it's fields over the top.
"There were police all over. We still didn't know the full extent of what had gone off."
Mrs Lacey said she heard a noise at Mrs Denby's house and thought the pensioner was being broken into but it was the police.
She added that she was distraught when she realised her neighbour had died.
"I just broke down. I was sobbing... sobbing.
"She was everyone's grandma. She was a lovely lady - just the type of person you want for your nana.
"She didn't harm anyone. She was always in her garden, she loved it.
"For something to happen on your own doorstep like this, it's a nightmare. You just don't believe it.
"I'm in shock that someone could hurt an old lady - she was an old lady, for God's sake."
Mrs Denby's next-door neighbour, Jackie Smith, said: "She was such a good neighbour and she was really respected down this road.
"She was my husband's school teacher and then, when she moved in, she'd say, 'Hiya, Michael, I remember you'. She was absolutely lovely."
Mrs Smith said she got increasingly worried by the police activity and then heard officers break down her neighbour's door.
"I just can't believe it. It's just awful," she said.
Mrs Smith said Mrs Denby had lived at the address for about 23 years, and her mother lived there before her.
Local retailer Chandrika Patel, whose shop backs on to the park, said she and her customers were taken aback when they heard how events had unfolded.
"He's such a good lad," she said. "He's always playing outside and sometimes comes in here.
"Everyone's shocked by it all. It's a friendly area."
David Jacobs, who lives near Mrs Denby, said: "I know the little boy because he plays with my son. It's tragic.
"He's a very nice, normal lad who likes to play on his scooter and at the park and play on his bike.
"You can't understand why someone's done that to a little lad like that."
Mr Jacobs said: "People are scared to let their kids out. They're all going to keep them in tonight.
"You think, 'Is it safe any more?'".
Speaking at the skate park, Detective Superintendent Lisa Griffin, who is leading the police inquiry, said events unfolded when the boy was stabbed at about 4.40pm yesterday. He was airlifted to Leeds General Infirmary where he remains in a stable condition.
Ms Griffin said: "The nine-year-old boy was out playing and was returning home for a drink when he was approached by the male suspect and, with no prior warning and for no reason known to us at this time, he was attacked with a knife - a single stab wound causing him injuries to his chest and his arm."
The incident involving the girl happened about 10 minutes later in nearby Prospect Grove. The detective said the girl was not hurt and did not mention seeing a weapon. The man ran off when she screamed.
Following these incidents a full-scale police operation was launched that led to discovery of Mrs Denby's body just before midnight.
"It's my belief at this time that the three incidents are linked," Ms Griffin said.
Police said the 26-year-old man now in custody was spotted by a member of the public in Westfield Lane, Idle, Bradford, at 4.10am today and detained by officers.
Four other people have been arrested and Ms Griffin stressed her officers were not looking for anyone else in connection with the three incidents.
Police said another 26-year-old man has been arrested in connection with the murder. Three other local men - aged 18, 24 and 29 - have been arrested over the incident in the skate park.
The detective confirmed that a knife had been recovered
She said police and forensics officers were working on 10 different scenes in the area.
Police later said the 24-year-old was released without charge.