Neighbors Ann Bilansky and Lucinda Kilpatrick stopped at a St. Paul drugstore while running some errands in late February 1859. Bilansky spent 10 cents on a jar of arsenic, saying she needed it to poison the rats that had been chewing up vegetables in her cellar.

Two weeks later her 52-year-old husband, Stanislaus Bilansky, died. He was buried after a coroner’s jury ruled it a natural death. That night Kilpatrick told Police Chief John Crosby what she hadn’t initially divulged — that her friend had just bought arsenic.

Stanislaus’ freshly buried corpse was exhumed the next morning and a single crystal seen through a microscope “resembled arsenic,” according to a local druggist.

That sketchy scientific evidence led to Ann Bilansky’s gawker-filled hanging at 5th and Cedar streets in downtown St. Paul. She became the first white person legally executed in the 48 years that Minnesota doled out capital punishment — and the only woman ever killed by the state.

“She procured poison and then administered it. ... She sat by the bedside of her husband, not to foster, but to slay,” Gov. Alexander Ramsey wrote in vetoing legislation to commute her death sentence to life.

More than 160 years later, Ann Bilansky’s execution remains punctuated with question marks: Were both Ann and Lucinda involved with the same blue-eyed carpenter, John Walker? Did the financially strapped Stanislaus poison himself, something he’d apparently attempted before? Did Ramsey veto the bill that would have saved Ann to protect his brother Justus, who sat on the jury that convicted her? If innocent, as she maintained right up to the gallows, why did Ann break out of jail and hide near Lake Como — only to be arrested a week later, dressed in men’s attire and headed on foot with Walker to St. Anthony?

“It is impossible … to determine with certainty whether justice was served by the conviction of Ann Bilansky,” Matthew Cecil wrote in an extensively researched article for Minnesota History magazine in 1997. “As to the murder charge, reasonable doubt appears to exist. … The trial was clearly flawed.”

Before the hangman slipped a black cloth bag and noose over her head, Bilansky said she was made a sacrifice to the law. “I die without having had any mercy shown me, or justice …” she said. “Your courts of justice are not courts of justice, but I will yet get justice in heaven.”

Bilansky was believed to be 40 when she was executed. Born in North Carolina as Mary Ann Evards, she went by her middle name and was widowed when her first husband was killed in a railroad accident. She came to St. Paul from Illinois in 1858 at Walker’s request.

Stanislaus Bilansky, a Polish immigrant, had been among the first white settlers to arrive in Minnesota Territory in 1842. His second wife testified that he was abusive, moody and drank to extreme. She left him with their three kids.

Ann had no children of her own but took good care of her stepchildren after marrying Stanislaus five months into her move to St. Paul. They lived in a cabin that served as a bar and grocery on Stillwater Road, later E. 7th Street.

The love triangle centered on Walker. Ann said he was her nephew and that she’d come to help care for him when he contracted typhoid fever. Prosecutors countered by saying Ann Bilansky had “lived on improper terms” and “occupied the same room” as Walker, her extramarital affair being the motive for poisoning her husband.

Kilpatrick, the pivotal witness, might have been Walker’s lover, too; they all lived near one another. Under cross-examination about her relationship with Walker, Kilpatrick said “our friendly terms were broken up” and a “coldness commenced.” That might have given her a motive to poison Stanislaus.

Then there was the victim’s history.

A neighbor testified that Stanislaus was deep in debt and often said he’d just as soon “die as live.” Ann Bilansky’s attorney told the court that he “at one time did in fact take poison for self-destruction,” when his second wife left him.

The same day in July 1859 that the Minnesota Supreme Court rejected her appeal for a new trial, Bilansky met with Walker in the Ramsey County jail and then lingered in the hallway after dinner, talking to a jailer. When he went to fetch some keys, she escaped between the bars of a jail window. After she was arrested with Walker, a grand jury declined to indict him. But she was headed for the gallows.

“If I die in this case, I die an innocent woman,” she said at her sentencing. “I don’t think I have had a fair and just trial.”

Ann Bilansky was hanged on March 23, 1860, in Court House Square. The day before, her prosecutor asked that her sentence be commuted.

Isaac Heard said he carried “grave and serious doubts as to whether the defendant has had a fair trial.” Gov. Ramsey let the execution proceed.

Curt Brown’s tales about Minnesota’s history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com. His latest book looks at 1918 Minnesota, when flu, war and fires converged: http://strib.mn/MN1918.