THE coroner who has been asked by Durham Police to investigate the deaths of 12 patients of former family doctor Howard Martin said today he may examine further cases.

Dr Martin 71, was acquitted of killing Frank Moss, 59, Stanley Weldon and Harry Gittins, both 74, by injecting them with large doses of painkillers, following an eight-week trial at Teesside Crown Court this week.

Durham Police said yesterday that despite the not guilty verdicts, they would pass 12 more files of patient deaths where morphine may have been a significant factor to coroner Andrew Tweddle for his investigation.

At his office in Crook, County Durham, Mr Tweddle said: ''It is possible that when I have had opportunity to consider in detail these various files, that I may require further inquiries to be carried out.''

The coroner read a prepared statement in which he said police believed a number of patient deaths ''may have been unnatural''.

He said: ''It is possible that members of the public will have been made aware of Dr Martin's trial and may report their concerns to the police also.''

Mr Tweddle said police investigations were ongoing and the Department of Health was also making inquiries and checking patient medical records ''to ensure that any potentially unnatural deaths are brought to my attention''.

He added: ''Accordingly, at the moment, I am unable to be exact as to how many deaths maybe reported to me.''

He said he could have the information handed to him before Christmas.

He added that he was unsure how many of these cases would result in inquests taking place.

He went on: ''People may be concerned as to when any inquests may be heard.

''I regret that at the moment I cannot give any indication as to when my inquiries will be complete - timings will depend on a number of factors, not all of which are under my control.

''I wish to undertake a thorough inquiry and thoroughness does not always sit easily with rapidity.''

Dr Martin, a father-of-four who has retired from practice in the Newton Aycliffe area of County Durham, now resides in Penmaenmawr, Gwynedd, North Wales.

His legal team said yesterday they did not believe fresh charges would be brought against him, in the light of the police announcement that the coroner would investigate more deaths.

In a statement, his solicitor, Sara Mason, said: ''Dr Martin is not in a position to comment in relation to any individual patients.

''But it is quite clear from the press release issued by Durham Police Constabulary, that the CPS has no intention of bringing any further charges against Dr Martin in relation to deaths of any former patients.''

Mr Tweddle said he would consider whether to review full inquests into the deaths of Mr Moss, Mr Weldon and Mr Gittins, whom the GP was cleared of murdering.

He said he would resume the inquest into the death of 85-year-old William Kerr, another patient of Dr Martin whose body was exhumed by police.

Dr Martin was never charged with his murder.

The jury unanimously cleared the former Army officer of killing his patients by injecting them with morphine.

He said after the trial he had been doing his duty as a GP by caring for them.