Amy Booth lost her fight for life last Tuesday – three weeks after an horrific attack at her flat in Wellington Place, Halifax, that left her beaten so badly she was almost unrecognisable.

Devastated staff and customers at the Bradshaw Tavern, where Amy was working part-time, have been collecting money for the 23-year-old and raised £770.

The money was meant to help with Amy's recovery. They say they are not sure how the money will be spent now.

Police have stepped up their investigation into Amy's attack to a murder hunt and West Yorkshire's Homicide and Major Inquiries Team is now involved.

Detective Superintendent Andy Brennan, who is leading the investigation, said a post-mortem examination carried out on Friday afternoon showed Amy died as a result of the injuries she suffered in the brutal attack at her home.

They have renewed their appeal for anyone with information to come forward.

They are still looking for a man, described as Asian, who was seen in the area when the attack happened shortly before midnight on December 8.

Amy's mother, who spent the days after the attack by her daughter's hospital bedside, made an emotional appeal for anyone who could help find the culprits in the Courier on Christmas Eve.

Then Amy had just come off a ventilator and was being cared for in the high dependency unit at Leeds General Infirmary.

Margaret Booth said her daughter – a former pupil at Brooksbank School, Elland, who also worked in the customer services department at First buses – was a popular girl who enjoyed listening to music and going out for meals.

She was due to move out of the Wellington Place flat to a new home when the attack happened.

Anyone with information should call police on 01422 337085 or CrimeStoppers on 0800 555111.

Suleman Mahmood Khan, 24, of Dunkirk Terrace, Halifax, has already been charged with wounding with intent to cause grevious bodily harm.

Two men, aged 32 and 25, and a 21-year-old woman have also been arrested and are on police bail.