She was later charged with prostitution under a controversial public order law. "We tried to tell them that it was a house and it was a normal meeting," she said.

"We told them there is no reason for policemen to break through a window suddenly and accuse us of things like this." 

Despite her protests, officers confiscated Omer's laptop and detained her for five days.

When her trial began on July 24, investigators told her she could face more charges, including espionage against the regime. 

Such a crime carries the death penalty, although in early August, she told AFP she had not been formally charged with spying. 

"I'm not scared to face the state in any court," said Wini, who last year was on a US government fellowship for young African leaders.

"What counts for me is that we pass our message to everybody in Sudan and to the oppressive state institutions, and tell them that we are not afraid and we are always ready to fight for our rights."

At a session of her trial earlier this month, police told the court that they raided the apartment in February after keeping it under surveillance for two weeks, Sudanese media reported.

"The police informed the court that when they broke into the apartment, they found the four accused fully dressed and involved in a discussion," Omer's lawyer Fateh al-Hussein said.

The public order law targets mainly women, activists say, including those selling tea on the streets of the capital. 

According to activist Tahani Abbas from campaign group, 'No to Women's Oppression Initiative,' 15,000 women were sentenced to flogging in 2016 under the legislation. 

The decades-old law also imposes punishments including hefty fines and jail terms. 

Activists say that nearly every gathering of Sudanese men and women, whether in public or private, can be a police target.

"Regulations like the public order law are tools used to harass activists fighting for human rights and to instil fear in the citizens," Wini, who is also a journalist and has written regularly on women's issues in the African country, explained.

"When they target activists, it's a message to them that they are being watched and the state will suppress them."

She was previously accused of breaching the law through "indecent dressing" while waiting for a bus in Khartoum, wearing a headscarf, skirt and top. The charge was later dismissed. 

'Keep fighting'

Despite the legal challenges, Wini has continued her campaigning work, which began when she was studying anthropology at university a decade ago.

She was in court in May when a Sudanese teenager, Noura Hussein, was sentenced to death for murdering her husband who Hussein says had raped her. 

Following international outrage, an appeals court commuted the sentence to a five-year prison term.

Wini at the time said the case illustrated how women's rights needed to be taken more seriously, in a country where forced marriage and marital rape are prevalent.

She says Sudan's legal system arbitrarily applies Islamic law along with tribal traditions, and discriminates against women.

"By allowing child marriages and imposing restrictions on women, the system wants women to be confined only to specific duties," she said.

But Wini acknowledged that Sudan is witnessing changes, with social media seeing growing debates on women's rights.

"Questions about whether women have the right to dress the way they want, whether they have the right to marry the person they want, are increasingly asked now," she said.

"I believe that change happens when you stand up and fight for your rights... We have to keep fighting for our personal rights."