SYDNEY (AP) — Australia's highest court on Friday threw out the conviction of an American surgeon accused of the manslaughter of three patients and ordered him to stand trial again, after ruling that conduct by prosecutors had led to a miscarriage of justice.

Jayant Patel, an Indian-born U.S. citizen, was sentenced to seven years in prison in 2010 after being convicted of three counts of manslaughter and one count of causing grievous bodily harm. The accusations related to his work as chief surgeon at a public hospital in Queensland state between 2003 and 2005.

During the trial, prosecutors accused Patel of misdiagnosing patients, using sloppy, antiquated surgical techniques and performing surgeries he'd been banned from undertaking in the U.S.

Patel pleaded not guilty, and his lawyers' appeal of the conviction argued that prosecutors radically and unfairly changed tactics late in the trial.

Patel's conviction came more than 25 years after concerns were first raised in the U.S. about his competency as a surgeon. When colleagues and patients began sounding the alarm about his alleged behavior in Australia, he left the country and returned to the U.S. The FBI arrested him in Portland, Oregon, in 2008 and he was extradited to Australia.

A government inquiry initially found that Patel may have directly contributed to 13 deaths at the hospital in Bundaberg, a sugar industry town 370 kilometers (230 miles) north of Brisbane. By the time the case went to trial, prosecutors had narrowed the case to three counts of manslaughter for the deaths of Mervyn John Morris, James Edward Phillips and Gerry Kemps, and one count of grievous bodily harm for his treatment of Ian Rodney Vowles.

The prosecution initially accused Patel of being incompetent and negligent in three areas: his recommendation of certain surgeries, the way he performed those surgeries, and the care he gave patients after their surgeries. Late in the trial, however, the prosecution narrowed its case to focus only on whether the surgeries should have been performed at all.

In its decision to throw out the conviction on Friday, the High Court in Canberra wrote that it became clear during the trial that Patel had performed the surgeries "competently enough."

"The prosecution then radically changed its case, at a late point in the trial, to focus on the appellant's decision to undertake the surgical procedures," the court wrote. "Much of the evidence about the surgery and post-operative care was prejudicial to the appellant but no longer relevant on the prosecution's revised case."

That evidence prejudiced the jury, resulting in a "substantial miscarriage of justice," the court wrote.

Patel has never spoken publicly about the accusations. He was granted bail within hours of the court ruling.

Beryl Crosby, who runs a support group for those who say they were harmed by Patel, said she and other former patients were devastated by the court's decision.

"I don't think words can tell you how this has emotionally affected everybody here," Crosby said. "It's just the worst case scenario."

A new trial date has not yet been set.