Wiltshire police have been battling to find out the truth but the mother of university student Rachel Whitear is likely to never know who administered her daughter's last fatal injection of heroin because of mistakes made by another force.

Yesterday an inquest jury said it could not rule out the possibility that someone else had been in the room and injected the 21-year-old student with the drugs.

Her mother Pauline Holcroft is no doubt who is to blame for the many unanswered questions that have haunted her since be body of her daughter was found in an Exmouth bedsit seven years ago.

Yesterday the battling mother blasted the Devon and Cornwall police and coroner for denying her the truth by treating the death of the former Bath University student as an inconsequential statistic and not investigating it properly.

For seven years she has virtually been gagged by the fear of legal proceedings or compromising the fresh inquiry she desperately wanted into the death of her daughter.

When she made the Rachel's Story video about her daughter's descent from bright student to heroin addict, she could release the pictures of her dead body but had to carefully censor the last chapter.

But yesterday Mrs Holcroft was able to speak out and tell the world that she had always believed someone else was in the room when Rachel died but would never be able to prove it.

She said: "At the conclusion of this inquest Mick and I, our family and friends, remain steadfast that we know the circumstances surrounding Rachel's death. It seems inevitable and with regret that we will never be able to prove this.

We know that we aren't here to apportion blame for the death of our daughter, but we cannot ignore the fact that the reason we are here at all is because of the incompetence of those officers from Devon and Cornwall Police who attended the scene when Rachel's body was discovered.

"We believe this was compounded by the outright negligence of the coroner, his office and the pathologist."

She added: "Everything about the scene; the posture of Rachel's body, the position of the syringe, the tidiness of the room, the towel placed so carefully over the door, we are in no doubt these are all highly suspicious and warranted detailed investigation.

"No forensic examination was carried out, and an investigation carried out four years later was sadly too late," said Mrs Holcroft, who added: "An external examination was not carried out on Rachel's body and again more assumptions were made."

She said their only regret was that none of the officers who went to the scene of her daughter's death were called to the inquest to explain their apparent apathy that night.

Mrs Holcroft and husband Mick were never happy with the original investigation and inquest into Rachel's death in December 2000 where they found out that toxicology tests were inconclusive and a post-mortem examination was not carried out.

The couple said the open verdict raised more questions than answers about the last days and hours of the piano-playing young woman who had abandoned her degree at Bath Spa University to move to Exmouth with Luke Fitzgerald, her longstanding boyfriend from her home town of Hereford.

After completing a new investigation into her death, Wiltshire Police went to the Attorney General for a fresh inquest which allowed Mrs Holcroft to air the questions that had been keeping her awake at night ever since.

Friends, including Polly North, told the inquest that heroin addict Mr Fitzgerald was violent towards Rachel and had given her a black eye shortly before her death.

But after her body was exhumed in 2003 a pathologist was able to reassure the family that Rachel did not suffer any broken bones or trauma and that she had in fact died of a heroin overdose.

Whether it was Rachel or someone else who gave the fatal injection two days before her body was discovered, on Friday, May 12 is what they will never know.

The jury decided it did not know either after hearing conflicting reports at the five-day inquest at County Hall, Exeter .

An anonymous witness told the jury that Mr Fitzgerald's brother Simon had told her that Luke had given Rachel the injection before storming out of the bedsit.

She claimed Luke returned to find her dead and Simon rushed down from Hereford to reposition her body and remove all signs of Luke's involvement, including placing a clean syringe in her hands. But Simon Fitzgerald issued a statement denying the story and Luke Fitzgerald took to the stand to tell her parents that he did not even know the address of the Pound Street bedsit where Rachel had moved the day before she died.

He admitted he had introduced Rachel to heroin, that at times he had injected her, that he was angry when she left him to start a new life and that he had shown little compassion when told of her death.

He even admitted lying to police about seeing Rachel on the day she died. But he addressed the allegations against him head on and flatly denied ever being at Rachel's new bedsit or giving her the fatal injection.

Scenes of crime officer Kevin Morgan said there was nothing to arouse his suspicions but admitted that in 38 years he could not recall seeing a drug fatality holding a capped needle, and had never seen one on their knees.

Opiate expert Professor Alexander Forrest said no heroin was found in the needle Miss Whitear was holding, implying it had been washed or never contained the drug, and it was possible the body had been posed after death.

Rachel's drugs counsellor was one of the last people to see her alive on Wednesday May 10, the day she died, and said she had not taken drugs for a week and was upbeat, positive and making plans.

He said Rachel could have died from a particularly pure form of heroin or because her tolerance levels had been reduced because she was trying to kick her addiction.

Detective Chief Superintendent Paul Howlett, led the Wiltshire Police reinvestigation into Rachel's death and is preparing a report for the Independent Police Complaints Commission.

Two men were arrested but released without charge when the file was sent to the Crown Prosecution Service.

He said after the inquest: "There are many things we are unable to explain. It was feasible a third party might have been able to enter and exit her room at the time of her death. But there was no evidence to corroborate this actually happened, and in particular that Luke Fitzgerald ever visited Pound Street."

Yesterday was a major milestone in the battle to get the truth which started seven years ago when the Holcrofts went down to Exmouth hoping Rachel was kicking heroin and starting a new life, only to get a phone call to say she had been found dead.

There is nowhere else to go and Mrs Holcroft, who is writing a book, says her battle for the truth has taken a toll on the whole family.

She said: "Having introduced our daughter to heroin, Luke Fitzgerald has apparently moved on with his life. Heroin saw that Rachel was not afforded the same opportunity. We are left to only imagine the beautiful, talented and mature young woman who could have been standing before us today."

Mrs Holcroft also criticised the Fitzgerald family for hanging on to Rachel's belongings.

The keepsakes, which included a Bible, school report and family letters, were handed back via the detectives handling the inquiry.

Exeter Coroner Ian Arrow said many organisations had learned from the death of Miss Whitear and had modified procedures and he hoped it would help to promote better practices in future.

But the family hope Rachel's lasting legacy is that other young people will turn their back on drugs.

"Drug addiction is not pretty, it is not glamorous and it hurts badly," said Mrs Holcroft. "If nothing else comes from this process we hope it sends a strong message to those involved in substance abuse."