Doctor cleared of murder investigated over 12 other deaths

Dr Howard Martin, a retired GP cleared of murdering three patients with massive morphine overdoses, is to be investigated over his role in the deaths of a further 12 people.

Dr Martin, 71, who practised for a time in the same surgery as the serial killer Dr Harold Shipman, was cleared by a jury at Teesside Crown Court of killing Frank Moss, 59, Stanley Weldon and Harry Gittins, both 74.

But Durham Police said the coroner, Andrew Tweddle, is to examine three "in-depth" criminal investigations of the deaths of women aged 61, 54 and 78, plus "mini-files" on seven men aged between 58 and 86, and two women in their sixties. The coroner is now investigating the cases of 16 patients treated by Dr Martin, the 12 new cases plus those of four whose bodies have been exhumed, Mr Moss, Mr Weldon, Mr Gittins and 84-year-old William Kerr, whose death was not subject to criminal proceedings.

Within days, medical specialists from the Sedgefield Primary Care Trust (PCT) are expected to deliver the findings of a review of Dr Martin's patient records from 1994 to December 2001. This may result in "more cases being passed to police for further examination on behalf of the coroner", said Detective Superintendent Harry Stephenson, who has led the criminal investigation into Dr Martin.

On Wednesday, Mr Stephenson took the highly unusual step of questioning the acquittal of Dr Martin after a six-week trial during which the retired GP relied on expert testimony rather than testifying in his own defence. Durham Police have not ruled out re-interviewing him.

Sedgefield PCT confirmed that Dr Martin and Dr Shipman had worked at the health centre at the same time, though detectives said any relationship between the two had never figured in inquiries.

The 12 new cases, not brought to court because they failed a four-point criteria test based on forensic evidence, medical records and witness statements, do not include that of Dr Martin's son, Paul, who died aged 31 of cancer in 1989.

During Dr Martin's trial Harry Gittins' daughter, Jillian Coates, said Dr Martin had talked of his former wife. "He said his son had died of cancer and he had administered drugs to his son, and his wife had not been very happy about the way he treated his son," Mrs Coates told the jury.

Police said they were alerted in December 2000 after the death days earlier of a 61-year-old woman at home in a village in Co Durham. Macmillan nurses had questioned Dr Martin's management of her care. After investigation, police and a Home Office pathologist concluded on the evidence available then that the treatment had been "acceptable". This death is among the 12 being handed to the coroner. Mr Stephenson said 28 complaints had been referred to police, by relatives or from the local PCT.

The investigation began after Mrs Coates told police of her concerns about how her father died. It initially concentrated on the period between January 2002 and May 2004 but also embraced relatives' concerns as far back as 1978.

That led to late-night exhumations and the biggest murder investigation in the history of Durham Police. Nearly two years later, Dr Martin, who now lives at Penmaenmawr, North Wales, walked free and called his trial "eight weeks of hell on earth".

At the High Court in London, the General Medical Council obtained an order suspending Dr Martin from being able to practise as a doctor for a further four months. His existing suspension "to protect the public" expires on 6 January.