by Lynne French BBC News South West

There is no evidence to show the Fishers knew their killers

In November 2003 Det Supt Stuart Newberry was only a few months away from retirement, having completed more than 30 years with Devon and Cornwall Police.

But the most difficult case of his career, the savage murder of Graham and Carol Fisher at their Wadebridge home on 5 November, put paid to that.

Their deaths sparked a two-year murder inquiry so complicated that, as the senior investigating officer (SIO), Mr Newberry postponed his retirement by 12 months.

On Thursday the professionalism, hard work and dedication of everyone involved in the murder investigation was rewarded with the conviction of brothers Lee and Robert Firkins.

Carol Fisher's body was discovered by a school bus driver just before 0900 GMT on 6 November.

Officers from an armed response team found her husband Graham's body in their bungalow behind the garage they owned.

It must have been absolutely terrifying for the couple Det Supt Stuart Newberry (retired)

When the bodies were discovered, the television was still on and a pie in the oven was burned to a crisp.

The couple had been subjected to a terrifying ordeal at the hands of their killers.

Graham Fisher had been shot twice and then bludgeoned to death with a sledgehammer.

His wife was shot in the hand as she tried, but failed, to make an emergency 999 call.

She had managed to escape from the house, but was shot twice more before she too was battered with a sledgehammer.

It is thought the sound of gun shots could have been masked by fireworks.

The level of violence used against the Fishers shocked not only the local community but many hardened police officers.

The Fishers were shot then bludgeoned with a sledgehammer

Mr Newberry described the scene confronting officers as "almost beyond belief".

"It has been a really difficult investigation. The sheer horror of the events which started to unfold from Perch garage on 6 November gave us a real task.

"It must have been absolutely terrifying for the couple."

At the height of the two-year investigation, more than 100 officers were working on the case.

The savagery used against the couple suggested to some that the murders must have been personal, yet there is no evidence to suggest the Fishers knew their killers.

Police said robbery was the obvious motive, but the painstaking investigation has never been able to establish exactly what, if anything, was taken.

Open safe

Mr Newberry said that if robbery had been the motive, it was a "bungled" one and several target items which should have been taken were not.

The door to the couple's safe was lying open, papers were strewn over the floor, but about �2,000 in cash was untouched.

"We don't know what was stolen," said Mr Newberry.

"We do know what was left, but we don't know what was there to begin with."

Det Supt Newberry finally retired in March 2005

When the crime was discovered and police entered the small bungalow, they found it so cluttered and crammed full of belongings, that it hindered their search for evidence.

"The scene itself was very difficult. There was a lot of stuff in the place and it looked as though the Fishers had never thrown anything out," said Mr Newberry.

"They just seemed to store everything. There were some rooms you couldn't actually get into because of the sheer bulk in the way."

To help establish what may have been stolen and a possible motive for the murder, officers emptied the bungalow and removed the contents to a hangar at nearby RAF St Mawgan where every item was painstakingly sifted and sorted.

Reward offered

No fingerprints or forensic evidence were found at the scene, nor were there any witnesses to what had happened.

Codenamed Operation Rowan, the murder investigation was featured on BBC's Crimewatch programme and a reward of �10,000 was offered by Crimestoppers.

During the course of the prolonged investigation a series of arrests were made across the country with the aid of other police forces.

But it was not until October 2004 that brothers Robert and Lee Firkins, who had twice been arrested and released, were charged with the double murder.

The former SIO told BBC News the turning point in the investigation was a forensic link between the Firkins and another armed robbery using a double barrelled shotgun which took place in Cornwall six weeks after the murder of Carol and Graham Fisher.

Mr Newberry said it was a huge relief the investigation was over and described the brothers as "formidable, ruthless and incredibly violent".

Robert and Lee Firkins, originally from Dagenham in Essex, had previous convictions for violence, robbery and carrying guns.

They claimed at one time to have been forced out of London by gangland bosses.