KNOXVILLE, Tenn. (AP) – A former nurse surrendered Thursday on a murder charge in the death of her first husband, a district attorney who authorities initially believed was accidentally killed 16 years ago when he was trampled by cattle.

Raynella Dossett Leath, 59, also faces a murder charge in the death of her second husband. Prosecutors have said there are similarities between the two cases. She was the first person to find both men and call police, and prescription drugs possibly played a role in each of their deaths.

The widow was indicted this week in the 1992 death of former prosecutor William Edward Dossett, 44, who was found dead in his pasture. His breastbone and some ribs were broken and he had a hoofprint on the chest of his overalls. Officials originally concluded he was knocked down by his cattle and ruled it an accidental death.

But an investigation into the 2003 death of the ex-nurse’s second husband prompted authorities to reopen the prosecutor’s case.

A medical examiner testified toxicology reports completed after the district attorney’s autopsy and burial in 1992 indicated he may have died from an overdose of morphine.

Dossett had a surgically installed morphine pump to treat pain from terminal cancer. Experts testified that he had more than double the recommended level in his system. It was “sufficiently high to be the cause of death,” Medical Examiner Darinka Meluesnic-Polcha said then.

Dossett Leath contends her second husband’s death was a suicide, but prosecutors suspect foul play because painkillers and antidepressants not prescribed to him were found in his system. She was charged in his death in 2006, and her trial is set to begin in September. David Leath, 57, was found shot in the couple’s bed.