Two anonymous letters have been sent to police investigating the death of a woman found stabbed to death at her cottage.
Betty Yates, 77, was found with stab wounds to the neck in her cottage by the River Severn in Bewdley in Worcestershire on January 4.
Police say the letters, received this week, contain information which have sparked potential new lines of inquiry and are urging the authors to contact them.
Officers also want to hear from a man who was seen walking along a lane close to the cottage on the night of January 2.
The man is described as white, in his 20s, and was wearing a thigh-length dark coloured jacket.
However police stressed the sighting was one of many current lines of inquiry they were following up.
Mrs Yates was found stabbed to death at the foot of her stairs in her cottage, Riverscroft.
The retired schoolteacher had also been attacked with one of her own walking sticks, police said.
It is believed she was killed on the evening of January 2.
Search teams have combed surrounding fields and woodland for clues.
Detective Chief Inspector Neil Jamieson, who is leading the murder inquiry, said: "Although those searches have been completed there is still a lot of forensic work ongoing at the cottage itself and that will continue for some time. We also continue to study CCTV.
"It is now more than a fortnight since Mrs Yates was found murdered but information is still coming in from members of the public through a variety of sources.
"In the last few days alone we have had several new sightings of considerable interest reported to us and those are being followed up."
He added: "This was a vicious and cruel attack on a pensioner who was living alone and unable to defend herself. Although such crimes are fortunately extremely rare it has obviously shocked the local community and everyone involved.
"We will not rest until we have got to the bottom of this and we are confident someone out there has some idea who has done this and why. I would appeal again for them to get in touch and tell us."
Anyone with information is urged to call the police on 0300 333 3000, or Crimestoppers anonymously on 0800 555 111.