It all began with a beauty pageant. There were multiple outfit changes, from evening gowns to bathing suits to national costumes. There were behind-the-scenes looks at the contestants’ lives. There were question-and-answer periods. And by the end of the 2023 Miss Universe competition last month, Sheynnis Palacios of Nicaragua emerged victorious.

People celebrated in Nicaragua’s streets, singing the national anthem and waving the country’s blue and white flag. It was the first time a contestant from the Central American nation of nearly seven million people had claimed the Miss Universe crown.

“It was as if someone had won the World Cup,” said Gioconda Belli, a well-known Nicaraguan poet and novelist.

Then came the government crackdown.

In what has felt like a script from a television drama, the authoritarian government claimed that the director of the Miss Nicaragua contest, which had chosen Ms. Palacios to represent the country at the global competition, was part of an “anti-patriotic conspiracy” to overthrow President Daniel Ortega and his wife, Vice President Rosario Murillo.

Both the director, Karen Celebertti, and Ms. Palacios, 23, had taken part in large anti-government protests in 2018 that the Ortega government viewed as a challenge to its rule and which led to a brutal crackdown. Ms. Celebertti’s husband, Martín Argüello, was also involved in the 2018 protests.

President Ortega’s daughter-in-law, Xiomara Blandino, a former Miss Nicaragua and a former Miss Universe finalist, had criticized Ms. Celebertti’s organization last month, before Ms. Palacios’s triumph.

Since the Miss Universe competition in El Salvador, Ms. Celebertti’s husband and son have been arrested, said a person close to the family who asked to remain anonymous for fear of also being detained. Ms. Celebertti, who had been in El Salvador, was not allowed back into Nicaragua with her daughter and, while stranded in Mexico, she resigned from her post this past Monday, after 23 years in the job.

Those connected to Ms. Palacios and the Miss Nicaragua organization are the latest, if perhaps the most unusual, targets of the Nicaraguan government’s campaign against its opponents. It has arrested or expelled political rivals and charity groups, Roman Catholic bishops and nuns, writers and poets, musicians and journalists.

Ms. Celebertti and Ms. Palacios didn’t respond to requests for comments. But in an Instagram post announcing her resignation, Ms. Celebertti said that the Miss Nicaragua organization was “free of political roots.”

The Miss Universe organization, in a statement, lauded Ms. Celebertti’s work.

“We stand by our partners in asserting the transparency and integrity of their pageant,” the group said. “Going forward, we are seeking a peaceful resolution of the issues raised by the country of Nicaragua, as well as the safety of everyone associated with the organization.”

Ms. Palacios thanked Ms. Celebertti in an Instagram post, calling her a friend and mentor. “The love for our country shines in everything you do,’’ Ms. Palacios said.

Ms. Palacios, who moved to New York for obligations related to being Miss Universe, said in an interview with Univision that she was working on planning a trip to Nicaragua. “I know that in my country everyone is happy with the triumph, so no I’m not scared to return,” she said.

President Ortega, 78, came to power as a leader of the Sandinista National Liberation Front that ousted a right-wing dictator in 1979. He was president from 1985 to 1990, when he lost re-election, but was voted into office again in 2006 and since then has systematically taken aim at his critics.

In 2018, hundreds of thousands of demonstrators blocked streets and paralyzed the country to protest the government’s anti-democratic rule and cuts in social security. The Ortega government unleashed a violent response, leading to the deaths of hundreds of people.

A United Nations investigation released this year likened Nicaragua’s track record on human rights to that of the Nazis. The Inter-American Commission on Human Rights estimated in a September report that more than 2,000 people have been arbitrarily detained in Nicaragua since the 2018 protests. The authorities have also stripped citizenships, including that of the writer Ms. Belli, and seized the homes of its detractors.

The government has denied deliberately killing protesters, noting that at least two dozen police officers also died.

Vice President Murillo, who serves as the country’s spokeswoman, did not respond to a request for comment.

The government’s harsh response against a beauty competition underscores its tactics toward opponents.

“Ortega has a problem,” said Arturo McFields Yescas, a former Nicaraguan ambassador to the Organization of American States who resigned and denounced the Ortegas last year.

“What he can’t control, he robs or destroys,’’ he said. “The baseball or boxing champions, for example, have to pay tribute to the regime. If they don’t, they become targets. Sheynnis has something — she came from the bottom, she doesn’t owe anything to the dictatorship — and that makes her someone dangerous.”

Ms. Palacios, who grew up roughly an hour south of Managua, the capital, was raised by a single mother. While at college — which was closed by the Ortega government this year — she helped her mother make buñuelos, fried dough treats, to sell to help pay for school.

The day after Ms. Palacios won Miss Universe, the Nicaraguan government said the country was celebrating “its queen” with “legitimate pride and joy.”

But the authorities shifted their tone soon after large numbers of people took to the streets, waving the Nicaraguan flag. Public demonstrations are effectively prohibited and the government promotes the red and black Sandinista flag over the blue and white national one.

“People lost the fear,” Mr. McFields said, “and that’s the part that scared the dictatorship the most.”

Days after she won, Nicaraguan police prevented two artists from painting a mural of Ms. Palacios in the town of Estelí, according to local reports. A social media influencer, Geovany López Acevedo, was detained for defending Ms. Palacios from the criticism she received on a government-controlled television channel, local reports said.

Then, on Nov. 22, the vice president issued a vague denouncement of the “gross exploitation and the rough and evil terrorist communication that seeks to convert a beautiful and deserved moment of pride and celebration into a destructive coup.”

When Mr. Argüello and his teenage son, Bernardo Argüello Celebertti, returned to Nicaragua, the authorities showed up at a family house and later detained both of them, the person close to the family said.

On Dec. 1, the national police issued a statement accusing Ms. Celebertti, her husband and her son of participating “online and in the streets” in “the failed coup” of 2018.

The police also said that the family had turned the Miss Nicaragua franchise “supposedly dedicated to promote ‘innocent’ beauty contests” into “traps and political ambushes, financed by foreign agents.”

Mr. McFields said the language in the authorities’ complaint was part of the same playbook used against priests, journalists and other critics.

How long Ms. Celebertti’s family members will be detained or whether Ms. Palacios returns to Nicaragua remains to be seen.

“It’s like beauty meets Godzilla,” Ms. Belli said in a telephone interview from Madrid, adding, “It’s the threat of beauty against a regime that has shown a monstrous face.”

Yubelka Mendoza and Emiliano Rodríguez Mega contributed reporting.