Raphael G. Satter, AP

A British doctor who admitted shortening the lives of nearly 20 patients — including his own son — may face charges. Howard Martin, 75, was cleared in 2005 of murdering three patients with fatal doses of pain killer. He has since had his license revoked.

Now a dramatic confession to a national newspaper has prompted police and prosecutors to consider re-opening the case against him. Martin, whose videotaped confession was carried by the Daily Telegraph newspaper, said he had no regrets, claiming he acted out of Christian compassion to end the suffering of pain-stricken patients.  “My conscience is clear, I don't have anything to fear,” he said in an interview from his home.

Describing his decision to end the life of his son, Paul, who was suffering from cancer before his death in May 1988, he said, “What more could I do for him other than make sure he had dignity?”

But Britain's General Medical Council differed, calling Martin's behavior completely unacceptable and saying that in some cases there was no proof the patients were suffering. While many of the 18 patients he injected had only days to live, at least one patient — 74-year-old Harry Gittins — could have recovered from esophageal cancer had Martin not administered 200 milligrams of diamorphine the day before he died. Martin then lied to the family, telling them that Gittins' cancer had spread, the council ruled.

Martin had been charged with murdering Gittins, along with fellow patients Frank Moss, 59, and 74-year-old Stanley Weldon, but he was eventually acquitted. Gittins' son said he hoped the case against Martin would be re-opened.

A 2005 reform to the English legal system means that the principle that prevents people being tried twice for the same crime, known as double jeopardy, no longer applies. Defendants may be tried twice for the same crime if new and compelling evidence is brought to bear.