Student Seif Bedour wanted to support his friend, a witness in a high-profile rape case, by accompanying her to a Cairo police station when she was brought in by officers on Aug. 28 after offering to testify on behalf of the victim, his sister says.
At the station, Bedour was detained and has been held in jail for four months on morality charges, relatives and activists say, even though the then 14-year-old had no connection to alleged rape and was not at the scene when it occurred at Cairo's Fairmont Nile City Hotel in 2014.
Three sources close to Bedour said he was accused of drug abuse and debauchery. His lawyer could not be reached for comment. The public prosecution department was not available for comment and the state press centre did not respond to a request for comment from Reuters.
In addition to Bedour, two others who had come forward to testify in support of the rape victim - party organizer Ahmed Ganzoury and Nazly Karim, ex-wife of one of the defendants in the rape case - have also been detained and are being held in prison on the same drug and debauchery charges, sources close to them said. Their lawyer could not be reached.
Three other witnesses who also wanted to testify in support of the victim, including Bedour's friend, have been released after also being arrested.
The case against Bedour and the witnesses is running alongside that of those suspected of committing the rape.
Of nine men accused of the rape, five are under arrest and four are outside the country.
Some human rights activists say the arrests of the witnesses are part of a tendency by authorities to prioritise traditional social morality at the expense of women's rights.
They say authorities are trying to counter a growing movement against exposing sexual abuse in Egypt that drew comparisons with the international "#MeToo" campaign and helped encourage witnesses to testify about the alleged rape at the Fairmont in April 2014.
In the Fairmont case, a rooftop party took place at the hotel and later the same evening a woman was allegedly gang-raped at an after-party there.
Encouraged by the #MeToo movement, the alleged Fairmont victim posted an anonymous account online before filing a formal complaint in July saying she had been drugged and gang raped.
In a statement on Aug. 31, Egypt's public prosecutors said Bedour, now aged 21, and the five witnesses were being interrogated in connection with "ongoing investigations" in the Fairmont case, without specifying charges.
They said Bedour and the witnesses were tested for drug use, and two were subjected to "medical tests". In a report published in September, U.S.-based Human Rights Watch (HRW) said the tests were anal examinations.
Family and friends have pleaded for the release of Bedour and the two witnesses still being held, saying they did nothing wrong.
"Our lives have completely turned upside down," Bedour's sister, Nivan Bedour, said. The detainees' next hearing is on Jan. 2, when they could be released or kept in custody.
Ganzoury has been cooperating with prosecutors and sharing details of the party he has said he organised at the Fairmont on the evening of the alleged rape, which happened at an after-party later that night which he did not organise, according to a friend of his and a source close to the victim.
Karim, the ex-wife of one of the rape defendants, was falsely portrayed as the rape victim in an anonymous smear campaign on the web, her family says. Reuters has also seen that material.
Several friends and activists say Karim's mental state has deteriorated in prison.
Her mother, actress Noha al-Amrousy, wrote on the Free Nazly Facebook page: "Nazly shifted from being a courageous girl who would never back down from telling the truth to a cowardly, scared girl ... Is that what you want this generation to be like? To silence them so that they don't say the truth?"