To a tangled homicide investigation that includes a family's tightly held "shroud of secrets," strife between two brothers, and a mysterious note on a bank deposit slip left on Leisa Martin's grave, the Minnesota Court of Appeals has added "prosecutorial misconduct and the presentation of inadmissible evidence."

The 14-year pursuit of justice surrounding Martin's death was made all the more complicated in a very rare and strongly worded ruling this week by the appeals court dismissing a grand jury's second-degree murder indictment against one of her brothers, Troy Martin.

"In 30 years of practicing law, this is absolutely the most bizarre case I've been involved with," said John Undem, one of Troy Martin's defense attorneys. "... I don't lose sleep over cases very often. But this one haunts me."

Leisa Martin was a petite 31-year-old woman with brunette hair, and the two men walking the lonely woods along Roy Lake in Mahnomen County that October night in 1998 only stumbled across her shallow grave because they happened to be looking for firewood.

For more than 11 frustrating years, investigators chased nearly 1,000 leads trying to unravel the mystery of Martin's death, finally getting their break when her other brother, Todd Martin, blurted a confession to a deputy during a drunken-driving arrest in 2010.

Three days before Leisa Martin's body was found, early on Oct. 28 at their home in rural Bagley in northwestern Minnesota, he said, he, his sister and his brother had been drinking, then arguing. Things escalated and, in his version of events, Troy Martin restrained his sister. She had "snaked out" before, Todd Martin would testify, and restraining her, sometimes to the point where she briefly couldn't breathe, was the only way to settle her down. The brothers thought she had merely passed out from drinking, Todd Martin said, but after about 25 minutes, found she was dead from asphyxiation.

As for Troy, he maintained he had been sleeping through the argument, and was not involved in restraining his sister. Their father, Dr. Fred Martin, who held that his daughter's death was a tragic accident, testified that he thought Todd Martin had been responsible for Leisa Martin's death.

After Martin's body was hidden, the family had held its secret close, even as suspicion swirled around the brothers -- until Todd Martin's DWI arrest on Jan. 24, 2010, when it all came apart. About 2:30 in the morning, Todd Martin showed up at his brother's home, banging on his door, revving his engine and drinking, according to court documents. On the way to Clearwater County jail, he tried to strangle a deputy, ranting about "just [wanting] to end it," and mentioning his sister's name several times.

After his confession, both brothers initially faced identical charges of aiding and abetting second-degree manslaughter, aiding an offender and aiding and abetting interference with a dead body. However, Undem said, Todd Martin struck a deal with prosecutors in which he would testify against his brother in exchange for the most serious charges being dismissed. The remaining charges against Todd Martin are still pending.

It's clear from the Court of Appeals ruling that, when Troy's case came before the grand jury in Clearwater County, things fell apart again.

The case's prosecutors were Eric Schieferdecker of the state attorney general's office and former Clearwater County Attorney Jeanine Brand, neither of whom could be reached Wednesday for comment. In its critical review of the grand jury's proceedings, the court ruled that prosecutors, not identified by name, stepped over the legal boundary of advising jurors and participating in their deliberations by offering an opinion that appeared to help steer jurors toward indictment after they had reached a stalemate over which of the brothers had restrained Leisa Martin.

In another instance, a prosecutor told a grand juror that returning an indictment might induce a guilty plea, rather than leading to a trial -- adding that a trial might lead to a lesser offense being charged, along with the possibility of a lighter sentence.

Prosecutors also let stand an inference that Troy Martin had refused to take a polygraph test when, in fact, he had passed such a test convincingly. Todd Martin, on the other hand, had declined to take the test.

The appeals court also agreed that the prosecution's case was full of improper speculation and character evidence.

"Troy Martin has shown that the grand jury would not have indicted him without the inadmissible evidence presented and the prosecutorial errors affecting the grand jury's independence," the three-member panel of judges wrote.

Jurors also never got a chance to view an intriguing piece of evidence, because it was lost by investigators: A note scrawled on a bank deposit slip bearing the name of one witness suspected in helping move Leisa Martin's body was left on her grave in 2003. It was found by three of her friends visiting the site, and is addressed to her. Part of it reads: "My life is really funny now. Words cannot explain what I feel. I'm totally lost."

Now that the indictment against Troy has been invalidated, the Court of Appeals ruling means the only avenue for prosecuting Troy Martin for second-degree murder would be through a criminal complaint. Undem hopes it doesn't come to that.

"There's just no evidence that points to Troy Martin being involved in his sister's death. None," he said. If a complaint would be filed, "It would take a miscarriage of justice even further. I hope the attorney general looks at this case herself, and at the very least has it reviewed."

Jim Anderson • 651-925-5039 Twitter: @StribJAnderson