Asha Steven Mwakilasa, a 50-year-old tailor and fashion designer in Tunduma, which is in Momba district, agrees: “I came to realise it was not true.”
This does not stop her anxiety – especially if her husband or sons are out, but she says she is grateful that the police are now mounting patrols.
Momba district commissioner Elias Daniel Mwandobo told the BBC local investigations suggested there was deliberate criminal intent behind some of the incidents: “Individuals conspired to commit a crime and incite public panic for their own benefits.”
Another video recorded in Tanzania’s main city of Dar es Salaam shows a crowd marching a man down a dusty market street, pushing, grabbing and striking him and insisting he returns the genitalia, as the man pleads his innocence.
The BBC Disinformation Unit verified similar videos of attacks in Mozambique and Kenya.
Dozens of these recordings of mob violence, alleged first-person accounts, warnings about alleged incidents, commentary and videos framed as reports of events in particular areas are circulating across TikTok and Facebook.
Many of those analysed by the BBC, including some showing mob violence, remain online.
“We are reviewing the content shared with us and will take action on those that are found to violate our policies,” a Meta spokesperson told the BBC.
TikTok has yet to respond to a BBC request for comment.
With some social media creators, who warn viewers to be vigilant, it is often unclear whether they believe the claims or are primarily seeking engagement.
Alongside these posts, some users promote so-called charms said to protect against genital theft, while comedians have parodied the claims through comedy skits.
Smartphones and social media make rumours spread faster, reach larger audiences and become more difficult to control once they begin circulating, says author Julien Bonhomme.
His book, The Sex Thieves: The Anthropology of a Rumor, examines how hearsay about “sex thieves” spread and why people believe them.
People are not simply hearing claims that someone has lost his genitals – they are seeing distressed men say it has happened to them, or watching crowds respond to accusations, he says.
Videos shared on social media can make unverified claims appear more believable, he says, because of their immediacy, describing this as “one of the most significant differences” between the current digital environment and earlier outbreaks.
