Sources close to the murder investigation insisted that despite the lack of a breakthrough 51 days after Miss Dando was shot dead outside her home in south-west London the police had "no doubt" that the culprit would be caught.
Despite the expressions of confidence detectives admit they still have not answered any of the key questions surrounding the murder, including finding a motive.
Miss Dando was killed on 26 April by a single shot to her head from a 9mm handgun as she stood in front of her front door in Gowan Avenue, Fulham.
A source close to the inquiry said yesterday: "The shooting bears all the hallmarks of a very planned and precise homicide.
"It has clear hallmarks of determination, of professionalism," he added.
The remarks follow analysis by a criminal profiler who was asked by the Metropolitan Police to assess what the likely motive was for the killing. The profiler concluded that if the killer was a stalker or obsessed fan then there would be some evidence of Miss Dando being followed or pestered.
The police, however, have found no evidence despite trawling through surveillance film of her last hours alive, thousands of e-mails, letters, a diary and interviews with friends and colleagues.
The police source said: "We would like to think that there was evidence of Jill Dando being stalked, harassed, given unwanted attention - there was no evidence."
He added that inquiries into her personal life to try to identify possible suspects had found nothing to suggest she was not "pure and innocent".
The nature of the killing, which was clinically and professionally carried out, has now thrown attention back on to the involvement of a professional criminal.
Among the other lines of inquiry the murder team have investigated are an attack by a disgruntled patient of Miss Dando's fiance, Dr Alan Farthing, . Police have examined whether any patients have attempted to sue the hospital consultant or his practice but found nothing.
Detectives are continuing to make inquiries into Miss Dando's background to find whether there was anyone with a reason for wanting to hurt her.
The police are also analysing thousands of mobile phone calls made in Fulham at the time of the murder. This follows descriptions of a heavily sweating suspect seen fleeing the scene of the crime with a mobile phone. The police hope that they can trace the suspect via any calls he may have made although this process could take many months to complete and the telephone he was using may have been stolen.
Despite detectives' insistence that they are making progress in the investigation and they have many positive leads it is looking increasingly unlikely the killer or killers will be caught. An e-fit of the main suspect was released on April 30 but that has failed to provide a breakthrough.
The police admit they do not know the motive for the murder, whether one or two men were involved in carrying it out, who was the driver of a Range Rover seen in Fulham at the time of the murder and they do not have any scientific evidence apart from the fatal bullet and its casing.Reuse content