THE weapon used to beat murdered Beata Bryl around the head more than 21 times could have been a steering lock, police have said.

Miss Bryl, 23, was also probably unable to defend herself during the "sustained attack", before her body was eventually set on fire and dumped in woodland near Wooburn Common.

Police told a press conference at Amersham Coroner's Court on Wednesday that they were hopeful of finding her killers, despite inquiries so far failing to lead to a prosecution.

Detective Inspector Colin Seaton said: "We are very hopeful that we will get to the bottom of this eventually and prosecute Beata Bryl's killer or killers.

"We do have some lines of inquiry which I won't go into but this case is very much active."

Miss Bryl's body was found off Hedsor Lane on July 29 last year. It is believed she was set alight in an attempt to destroy any evidence.

DI Seaton said the 13 people arrested during the murder inquiry were unlikely to be reinvestigated. He said: "None of the people arrested we believe are responsible for her death."

The Polish woman's inquest heard the same day that she suffered severe fracturing at the back of her skull caused by at least 21 blows with a blunt instrument.

Dr Kenneth Shorrock, Home Office pathologist, said it was likely the weapon had a "threaded screw type pattern".

DI Seaton later clarified that a steering lock could have been used but the weapon has still not been found to this day.

Police have ruled out her death being linked to prostitution or organised crime. They say there was also no evidence that she was trafficked into the country illegally.

Dr Shorrock said Miss Bryl could have been sexually abused but tests had so far proved negative. He told the inquest she was likely to have died before being set alight as her lungs had not inhaled smoke.

Miss Bryl was last sighted on July 28 at Leytonstone underground station, in east London. She boarded a train at 11.39pm and headed westbound on the central line. Her movements after this remain a mystery. The clothes she was seen wearing on CCTV at the station were the same ones her body were found in.

DI Seaton said: "It was a violent attack. This certainly is the most violent I have seen."

The case was broadcast on the BBC's Crimewatch programme earlier this year, but police said some leads had proved fruitless. One included the arrest of a man whose business card was found in Miss Bryl's suspected rucksack. The rucksack, sighted on CCTV, has never been found, although a man rung the number on the card last year saying he had found a rucksack and didn't know who it belonged to. Police have still to discover who the caller was but arrested the man on the business card. He was not charged.

Coroner for Buckinghamshire Richard Hulett recorded a verdict of unlawful killing. The inquest was concluded to allow Miss Bryl's family to register her death. There is still a £10,000 reward for information leading to the conviction of her killer.

Contact police on 08458 505 505 or Crimestoppers on 0800 555 111.