A holistic health practitioner who was on trial after a patient died made a surprise guilty plea Wednesday morning after new evidence was discovered, the Jefferson County district attorney's office said.

When confronted with the new evidence, Brian Edward O'Connell, 37, pleaded guilty to theft, perjury, criminally negligent homicide, illegal practice of medicine and third-degree assault. Wednesday was the second day of jury selection and opening statements in his trial were set to begin Thursday.

O'Connell will be sentenced March 27.

Prosecutors say that the new evidence that they received Tuesday night concerned a previous trial. In that 1999 trial O'Connell had testified as an expert witness in the field of toxicology and had claimed to have various medical degrees. Prosecutors now know that he didn't have such degrees then and they planned to file an additional perjury charge.

When prosecutors confronted him with this new information Wednesday morning, O'Connell agreed just to plead guilty.

O'Connell was in charge of Mountain Area Naturopathic Associates in Wheat Ridge. In his office he displayed numerous degrees and certifications claiming he was doctor and a naturopath. The Colorado Medical Board found that he had no license to practice medicine in Colorado and was not certified as any kind of health care worker.

His trial involved the death of 19-year-old Sean Flanagan, who was taken to O'Connell's clinic for alternative treatment. Flanagan suffered from Ewing's Sarcoma, a form of cancer, and had tried chemotherapy and radiation treatment to no avail.

Flanagan's family said he died prematurely because of O'Connell's treatments.

Flanagan underwent a procedure known as ultraviolet blood irradiation, where his blood was removed from the body, passed under an ultraviolet light and then returned to the body. When he didn't respond well to that, O'Connell then treated Flanagan by injecting his blood with hydrogen peroxide.

The next day he died.

Prosecutors argued that Flanagan's cause of death was listed as probable complications from the hydrogen peroxide treatment.

O'Connell also injected this hydrogen peroxide solution into a 17-year-old girl, which caused her to go into cardiac arrest. Another patient of O'Connell's had terminal liver cancer and was told by O'Connell that a "black salve" compound would pull the cancer out of his body. Instead it created open, bleeding wounds that continued until his death, prosecutors said.