DETECTIVES will today reveal new details about the investigation into retired GP Howard Martin who was yesterday cleared of murdering three patients.

Durham Constabulary said last night that the investigation into Dr Martin was still going on.

The former County Durham GP walked free from court after a jury cleared him on three counts of murder.

Dr Martin, who had denied deliberately injecting Harry Gittins, Stanley Weldon and Frank Moss with lethal amounts of the painkiller morphine, said he had suffered a "hell on earth".

The 71-year-old was unanimously found not guilty on all three counts of murder by a jury at Teesside Crown Court following a trial that lasted almost six weeks.

Last night, angry relatives of the dead men said they were devastated by the verdicts.

Durham Police refused to comment on what announcements would be made at a Press briefing at force headquarters this morning.

But a spokesman said: "It is our intention to release a full Press statement about the next development in this detailed and continuing investigation."

Dr Martin, who worked for the Jubilee Medical Group, had been accused of killing 74-year-old throat cancer sufferer Mr Gittins, of Tattersall Close, Newton Aycliffe, who was treated at his home on January 21 last year and died hours later.

He was also accused of the murder of Mr Moss, 59, of New Row, Eldon, near Bishop Auckland, who was suffering from lung disease, and Mr Weldon, 74, of Kimberley Street, Coundon Grange, who had Alzheim-ers.

It was concerns expressed by Mr Gittins' family that sparked the biggest murder investigation in Durham Constabulary's history, which led to the exhumation of his body, along with the bodies of Mr Moss and Mr Weldon.

They had both died within four days of each other, in March 2003, after also being administered painkilling drugs by Dr Martin.

Yesterday, in Court Two, there was pandemonium for a few seconds when the verdicts were read out, with friends and family of Dr Martin jumping off their seats and punching the air.

But there were cries of anguish from the relatives of the three dead men.

Dr Martin smiled and clasped his hands together as the jury foreman answered "not guilty" to each of the counts.

The judge, Mr Justice Forbes, praised the jury and expressed his deep thanks for their efforts in what he called a "difficult, complex and distressing case".

They had spent more than six hours in reaching their verdicts.

Afterwards, Dr Martin's solicitor, Sara Mason, said: "Dr Martin has always maintained he was doing no more than his best to relieve the suffering of these three patients. He was legally entitled to do that, and indeed it was his duty as their doctor to do that.

"Being prosecuted for murder came as a particularly bitter blow as he has spent nearly 50 years of his life caring for others at personal sacrifice.

"He would like to thank his family, friends and very many of his patients for their unwavering support over the ordeal of the last 18 months."

Dr Martin, who left the court arm in arm with his solicitor, was asked how he felt about the verdicts, and said: "I'm very relieved."

The doctor, who now lives in Gwynedd, North Wales, added: "I have been under house arrest for a year-and-a-half, and the last eight weeks have been hell on earth."

Detective Superintendent Harry Stephenson, of Durham Constabulary, said the outcome of the trial represented one of his biggest disappointments in 31 years as a police officer.