A meticulous investigation

The investigation into the murder of Jill Dando took two years. The BBC's Danny Shaw looks at the scale of the inquiry.

They called the investigation into the murder of Jill Dando Operation Oxborough. It was the biggest murder inquiry carried out by the Metropolitan Police and the largest criminal investigation since the hunt for the Yorkshire Ripper.

The initial problem detectives faced was lack of evidence - no motive, no eyewitnesses to the crime, no murder weapon.

In contrast, there seemed to be too much peripheral information. So much, in fact, that Scotland Yard - who were already stretched dealing with the London nail-bombings - had to bring in extra staff and resources.

At first police concentrated on sightings near the murder scene. Within days they had issued an e-fit of a sweating man at a bus stop. It produced a massive response, but created confusion later over identification evidence.

Operation Oxborough

2 year investigation

2,400 statements taken

14,000 emails examined

486 names in filofax investigated

2,000 potential suspects

1,200 cars traced

45 police in murder squad

Then, beginning with Jill Dando's inner core of family and friends, detectives interviewed everyone connected with her. Past boyfriends were spoken to; those involved in a contract race to buy her house were also seen.

Police traced most of the 486 names in her Filofax, went through her letters and phone messages and examined some 14,000 emails sent to the BBC.

Next came the Range Rovers. One had been spotted jumping a red light in Fulham just after the murder, so that car had to be tracked down. Others were identified too - in all, police recorded the details of 1200 vehicles.

After six months, the 45-strong murder squad seemed no closer to solving the crime. One man had been formally arrested, but police said he was an attention-seeker, who at 6ft 4 inches tall did not fit the killer's description.

Loner theory

But - pointed in the direction by a psychological profile of the likely killer - police started to focus more closely on the theory that the murder was not carried out by a hitman, but a loner, an obsessive, a stalker.

Detectives spoke to experts in America about stalking and re-assessed their pool of some 2,000 potential suspects. They found that 140 had an unhealthy interest in Jill Dando.

DCI Hamish Campbell led the police investigation

One man they thought might fall into that category was Barry George. Messages about him had been sent to police in the days following the murder.

But detectives - snowed-under with other priorities at the time - failed to act until February 2000, when the order went out to trace, interview and eliminate him from inquiries.

Three months later, after he had given a statement to police - just one of 2,400 they took in the inquiry - Barry George became the focus of their investigation.

A static camera was set up outside his flat, ten minutes from Jill Dando's address, as a team of 50 officers began a covert surveillance operation.

Detectives unearthed circumstantial evidence they said linked him to the crime - and then following one of three searches of his home, a scientist made an important discovery.

In the inside pocket of an overcoat hanging over the kitchen door, he found a tiny particle, which he said could be firearms residue from the gun used in the shooting.

Barry George was duly arrested on 25 May 2000 and charged with Jill Dando's murder three days later. But the murder investigation did not end there. The police had to gather evidence to counter his alibi, carry out video ID parades and prepare witnesses for the trial.

That took almost a year in itself - half the lifespan of Operation Oxborough.