Police investigating the murder of an elderly woman and the stabbing of a boy have released four men without charge.
Louisa Denby, 84, was found dead at her home in Shipley hours after nine-year-old Jason D’Arcy was stabbed at the Carnegie Skate Park.
Four men, aged 18, 24, 26 and 29, have been released following questioning.
A 26-year-old man being held on suspicion of Mrs Denby’s murder and the attempted murder of the boy remains in custody, a police spokesman said.
Pupils and parents at Jason’s school are being offered counselling.
He is said to be in a stable condition in hospital after having surgery. Jason suffered chest and arm injuries during the incident which happened on Monday at 4.40pm.
Speaking in the House of Commons, Prime Minister David Cameron described the stabbings as “truly shocking”.
Louisa Denby has been described by neighbours as “absolutely lovely”.
Police officers were outside Jason’s school on Wednesday morning, handing out information leaflets about the inquiry and speaking to parents.
Det Supt Lisa Griffin said the stabbings and an incident in which an eight-year-old girl was chased through a garden were being linked and police were not looking for anyone else.
The 26-year-old man being held on suspicion of murder and attempted murder is believed to Mrs Denby’s grandson.
One man was released on Tuesday night, while the others were released earlier.
Anyone with any information can contact HMET Team 5 via 101 or call Crimestoppers, anonymously, on 0800 555 111.