His lips are pressed tightly together. His eyes stare straight ahead. And his thick beard appears streaked with gray.

A recently unearthed glass-plate photograph, about 150 years old, puts a new face on a pivotal figure in perhaps early-Minnesota’s grimmest moment.

Until now, historians had never seen an image of Capt. William J. Duley — the executioner on the day 38 Dakota men were hanged in Mankato after the 1862 U.S.-Dakota War. New Ulm researcher and author Elroy Ubl tracked down a descendant in Seattle who had inherited a family album of the glass-plate portraits, including her great-great grandfather’s.

Now we know what the hangman looked like at the largest mass execution in U.S. history. Just how history remembers Duley — as traumatized father, notorious executioner or out-for-himself promoter — remains a thornier question.

Three of Duley’s children — Willie (10), Belle (4) and Francis (6 months) — were killed in the conflict. His wife, Laura, was shot in the heel, witnessed at least one child’s slaying and was taken captive along with their son, Jefferson, and daughter. Emma. Some accounts said Laura was pregnant at the time and miscarried during her four months on the Dakota plains. She might have been raped.

Duley had somehow managed to escape the Dakota raid a few days into the war at a settlement along Lake Shetek — in the middle of modern-day Murray County in southwestern Minnesota.

Fifteen settlers were killed at Lake Shetek that Aug. 20, 1862, and eight were taken hostage. Three months later, a white trader and some sympathetic Dakota found those captives near present-day Mobridge, S.D., and swapped guns, blankets and horses to win their freedom. A cart brought Laura, her foot still wounded, through a blizzard to Fort Pierre.

Duley, meanwhile, had faced the anguish of not knowing his family’s fate. He signed up to fight the Dakota and joined the team erecting the elaborate scaffolding in Mankato. On the day after Christmas, 1862, President Abraham Lincoln had ordered the hangings of 38 Dakota.

Duley was selected to cut the rope that dropped the noosed men to their deaths at a ceremony attended by thousands of settlers, including 1,400 soldiers who surrounded the gallows.

At the time, Duley might have known that his wife was alive. Researcher Curtis Dahlin found a St. Paul newspaper from Nov. 29, 1862, reporting freed captives. Duley received a letter from Laura on Dec. 30, four days after the hanging. They would be reunited in Iowa in January 1863.

With no photos of the hanging, in part because cold weather fogged the early cameras of the era, the Duley photo is a major find.

“Of all the photos collected from this unfortunate series of events in 1862, the discovery of this Duley photo is by far the most historically significant one to come on the scene,” Dahlin said.

Duley spent only about a quarter of his life — about 20 years — in Minnesota. He was born in Ripley County, Ind., and moved to Iowa at 27. He married Laura a year later in 1848. Their lives quickly turned tragic. Two of their children drowned in the Mississippi River.

The Duleys moved to Winona County in 1856 and William served as a Republican delegate at the State Constitutional Convention the next year. His farm and sawmill endured heavy dam failures and financial setbacks.

So in 1861, he moved to Lake Shetek with several families. They’d all been duped into believing a village of 90 people existed on the lakefront. They found nothing there but vowed to make the best of it.

When the Dakota War broke out the next year, Duley’s name would be etched into state history.

“I think of him as an opportunistic self-promoter,” said Dahlin, who has researched and written extensively about the war. Dahlin takes issue with Duley’s ability to escape the Lake Shetek raid while his family members died or were captured.

“He was a politician and they are never shrinking violets,” Dahlin said. “I’m not sure how he was selected to cut the rope at the execution, but I suspect he let his interest in the job become known.”

The next year, Duley joined the U.S. Army’s punitive raids into the Dakota Territory. His wife reportedly lost her mind during captivity and became “a helpless imbecile” who later regained her wits, according to accounts from the period.

Unlike some men in 1862, who spurned their wives after alleged Dakota rapes, Duley stayed with Laura. They left Minnesota in the 1870s for Alabama, where he worked as a millwright. Late in life, they followed their son to Washington state, where Jefferson became police chief in Tacoma and his father worked as a carpenter.

William and Laura Duley are buried in Gig Harbor near Tacoma. He died within a month of turning 80. She died two years later, at 72.

Jefferson’s great-granddaughter in Seattle shared the photos of the Duleys with Ubl, who included them in his seventh book, “Historical Notes: A Glimpse at New Ulm’s Past.” (To order, e-mail: history@newulmtel.net)

That Duley descendant, who is 64, asked that her name not be included in this story — reflecting how emotionally charged this history remains 153 years later. Her great-great grandmother Laura “never smiled again,” according to stories passed down through the family.

“There are always multiple stories to tell about these kind of figures in history,” said Dakota scholar and author Gwen Westerman, who teaches at Minnesota State, Mankato. “I have no quarrel with this man. We remember these people as a part of a pivotal period in Minnesota history. And I think we can do that without laying blame or anger or vengeance.”

She acknowledged some Dakota would feel differently, viewing Duley as the man who killed their ancestors.

“We are the products and the results of some painful times,” Westerman said.

Curt Brown’s tales about Minnesota’s history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com