A horrific knife attack on a Bradford couple has left police baffled.

Diane Ruane, 51, was stabbed to death at her home in Laisterdyke on Tuesday afternoon just before 2.30.

Her partner, Christopher Ruane, 59, was seriously injured in the attack in broad daylight which police said appeared to be motiveless.

Diane Ruane, also known as Diane Kendell, was stabbed a number of times after she answered the front door of the couple's terrace home in New Lane.

Detective Superintendent Paul Kennedy of Bradford North police said: "The circumstances surrounding this brutal attack are very peculiar because it took place in broad daylight and there is no apparent motive.

"It appears to have been completely unprovoked and there is no suggestion that the couple had been targeted by the attackers who were two white males."

It is not yet known whether or not property was removed from the house.

Two men were seen running away from New Lane into Raglan Terrace after the attack.

No weapon has been found.

"We are now appealing for information from anyone who believes they may have seen the two men in the area at the time," said DS Kennedy.

One man was described as having blond hair and being skinny and with drawn features.

The other man was described as having a darker complexion and was wearing a bobble hat.

"I am hoping that the bobble hat worn by one of the men will trigger people's memories," said DS Kenn-edy.

"It is strange for someone to wear this type of hat on a hot summer's day."

Emergency services were called to the house by Mr Ruane just before 2.30pm.

"Mr Ruane reported that two men had entered the house and attacked him and his wife," said DS Kennedy.

Mr Ruane remains in the Bradford Royal Infirmary but police are hoping to speak to him about what happened over the next couple of days.

"In the meantime we are carrying out house-to-house enquiries and talking to members of the local community," said DS Kennedy.

Police said the victims were very well known in the community.

DS Kennedy said: "The couple, who were not married, but who had four or five grown-up children, had lived in the area for a long time and were known locally as the 'Ruaney's'.

"Their family, who also live in Bradford, want answers as to how and why this happened to their parents."

A 45-year-old man arrested in connection with the attack has been released on police bail pending further enquiries.

Anyone with information about the incident should call Bradford North police on 01274 376100.