MEXICO CITY — Yazmín Morales recalls weeping with rage after an encounter four years ago in the book-lined study of her country’s most respected statesman. Óscar Arias Sánchez, a Nobel Peace Prize laureate and former Costa Rican president, had pinned her against a door, she says, forcibly kissing and groping her.

Until last week, Ms. Morales kept the episode to herself. But after another woman came forward to file a criminal complaint against the former president alleging sexual assault, Ms. Morales summoned the courage to add her voice.

Ms. Morales, a former Miss Costa Rica, wanted a powerful criminal lawyer to represent her. She called one, then another. After a third also refused to take her case, she decided to act alone. Accompanied only by her half sister, she, too, filed a criminal complaint against Mr. Arias.

The case of Mr. Arias, who now faces accusations of sexual assault or misconduct from at least nine women, is emerging as the most significant of the #MeToo era in Latin America.

But it has also revealed just how difficult it is for women to seek legal recourse in cases involving powerful men. In a region where the laws lay out a progressive vision of women’s rights, the social and political barriers to exercising those rights can seem insurmountable.

On Sunday, the list of Mr. Arias’s accusers grew again when Carina A. Black, 52, a political scientist at the University of Nevada, Reno, told The New York Times that Mr. Arias tried to grope and kiss her in 1998, when he visited the university as a speaker.

As she took Mr. Arias around at meetings and events, Ms. Black said, she found herself alone in an elevator with him. He pushed her against the elevator wall, put his hand across her chest and tried to kiss her, she said.

“I pushed him, and I smacked him in the face,” she said.

But because she was not injured, it never occurred to her to file a report, Ms. Black said. She has decided to tell her story now, she said, in part so people will believe his first accuser.

“Arias is so powerful,” she said. “He has huge land ownership. He is so revered. In Latin America, the power is so tilted on the side of men. This behavior is what most women have grown up with.”

Gloriana Valladares, a lawyer for Mr. Arias, acknowledged that he faces two legal complaints, from Ms. Morales and the first accuser, Alexandra Arce von Herold, a psychiatrist and nuclear disarmament activist. Ms. Valladares said she would not comment because the preliminary stages of the proceedings are private.

Last week, Mr. Arias “categorically” denied Dr. Arce’s assault allegations, saying he had never acted in a way that disrespected the will of any woman.

Ms. Morales, 48, said that as she looked for a high-profile lawyer to represent her, she found that they all had some kind of connection to Mr. Arias. Two of the lawyers she approached were former justice ministers, and one had run for the presidency.

They all found an excuse not to help her. One said that he was a friend of Mr. Arias’s wife. Another said that he did not take sexual-abuse cases, and the third said that he was too busy, she said.

“They preferred not to get involved,” Ms. Morales said in a telephone interview. “I was scared. If the lawyers didn’t want to support me, nobody else would.”

Ms. Morales declined to name the lawyers. “I am already scared of Óscar Arias,” she said. “Giving more names would be even more difficult.”

When she arrived to file her complaint, she met with a prosecutor and a psychologist and was advised to find a lawyer. Her complaint was first reported on the website of the Costa Rican journalist Amelia Rueda.

Dr. Arce, 34, the first woman to come forward, is a psychiatrist at a state hospital in San José. She often met with Mr. Arias in her nuclear disarmament work, and said she was at his home in late 2014 when he came up behind her, touched her breasts and shoved his hands up her skirt, penetrating her with his fingers.

In an interview last fall, Dr. Arce said several people had cautioned her against going public. “People began to make me feel scared about my security — my physical security,” she said.

When Dr. Arce first posted her account on social media last year, a journalist friend persuaded her to take it down, warning that she could be damaged by the tabloid media.

Mr. Arias did not know Ms. Morales personally before he invited her to his house around Easter of 2015 to give her a book of his essays and speeches. (The editor of that book says that as she worked with Mr. Arias, he once put his hand on her leg and that he called her twice, insisting that she come to his house for a massage.)

Ms. Morales, who worked as a television host and model after winning Miss Costa Rica in 1994, posts beauty tips on her Facebook page and sells skin care products online.

For more than an hour, the meeting was cordial. Mr. Arias gave her a tour of his elegant home before signing his book.

But when she moved to leave, he pinned her against the door, pulled her head back and kissed her, pressing his body against hers and touching her breasts, she said. Shocked, all she could say was: “Don Oscar, I have to go,” using a respectful form of address in Costa Rica.