A post-mortem examination is due to be conducted on a pensioner who died following a savage attack in her home in Birmingham.
Emma Winnall, 93, died in hospital on Tuesday, nearly a month after she was found badly beaten in her bed in Moseley.
West Midlands Police said the widow's death came after complications arising from her injuries. She suffered a fractured skull and broken arm and had been in intensive care since the attack on May 1.
Superintendent Richard Baker, head of major crime at West Midlands Police, described Mrs Winnall's death as "desperately sad news".
He said: "Clearly, this has now become a murder inquiry. This was a shocking attack on a defenceless, elderly woman as she slept in her own bed.
"No one capable of carrying out such a despicable attack deserves protecting - I'm asking people to look into their consciences and if they have any suspicions about who may be responsible to contact police."
Detailed forensic analysis is continuing on items removed from Mrs Winnall's home in Pensby Close, and a Crimestoppers reward of £5,000 is on offer to anyone who provides information which leads to a conviction.
A 56-year-old woman and a 28-year-old man from the Hall Green of Birmingham were arrested in connection with the offence earlier this month and are due to answer police bail in July.
Mr Baker added: "Two people remain on police bail having been arrested in connection with the assault. However, our inquiries continue and I'm still appealing for anyone with information to come forward and speak to us in confidence."
Anyone with information which could assist the inquiry is urged to contact West Midlands Police on 101 or to call Crimestoppers anonymously on 0800 555111.
