A WOMAN who suffered life-threatening head injuries in an assault on Monday has died in hospital.

Detectives have launched a murder investigation following the death of 44-year-old Julie Cook at Poole Hospital on Wednesday afternoon.

And police are trying to track down "vital witnesses" who may have seen her as she was travelling on a train through Hampshire.

Dorset Police said her family had been informed and the coroner notified.

Ms Cook, from Bournemouth, was discovered with her injuries at just after 8pm on Monday at a property in Clarence Park Road, Pokesdown.

The circumstances were deemed to be suspicious and an investigation, led by Dorset Police’s Major Crime Investigation Team, was launched, with CCTV images released yesterday in a bid to track down "vital witnesses" to the incident.

Police said the woman was travelling with a man on the London Waterloo to Weymouth train on Monday afternoon, before the incident which led to her fatal injuries.

At 3.37pm, police said, the pair were seen to leave the train at Pokesdown Railway Station and engage in an “altercation” on the platform.

They then left the station, walking towards Christchurch Road, arriving at the address in Clarence Park Road at some point between 4pm and 4.30pm.

Detective Inspector Neil Phillips said: “We have now launched a murder investigation following the death of Julie Cook.

“As part of my investigation, I am trying to establish her movements in the hours before she was found seriously injured.

“I have released these details in the hope that someone may have seen the victim and a man travelling on the train, getting off at Pokesdown station or walking toward Clarence Park Road.

"I am particularly keen to trace two young women who were seen at Pokesdown railway station at the same time that day. One was carrying a white shopping bag and the other carried a handbag over her shoulder.

“I believe these women may have seen the couple on the platform or witnessed the incident and I have released CCTV images of them in the hope that I can identify them. I would ask these women or anyone who knows them to please contact me."

Detectives were yesterday granted a 36-hour extension from Bournemouth Magistrates to question a 36-year-old Bournemouth man who has been arrested on suspicion of murder.

He remains assisting officers with their enquiries.

Witnesses and anyone with information can call Dorset Police in confidence on 101 quoting Operation Oxbow. Alternatively, call the free and anonymous Crimestoppers line on 0800 555 111 where mobile phone tariffs may apply.