The family of a British filmmaker said they were "worried sick" today after he was arrested for the second time on a round-the-world trip.
Graham Hughes, 30, is being held without charge in Brazzaville, the capital of the Republic of Congo.
He had gone to the city as part of a challenge to travel to the 192 UN member states by public transport.
The video director sent a message to his family in Liverpool saying: "Arrested again. I'm spending the night in the police station, no charge, no lawyer, no sense."
Another message said: "They don't intend to let me go. No-one knows where I am."
The adventurer was also arrested in June on Santiago, the largest of Cape Verde islands, on suspicion of entering the country illegally.
But he was released without charge after a week, and his family are praying for a similar conclusion in the Congo.
His elder brother Alex Hughes said: "This is different to Cape Verde because that is a tourist destination, but the Congo is notorious and I know Graham will be really worried.
"Our mum is very shaken by this, it is her youngest son at the end of the day. We just want to get this resolved."
The filmmaker's phone, tapes, camera and passport have been confiscated.
A Foreign Office spokesman said: "We can confirm a British national was detained in the Republic of Congo on September 11. We are providing consular assistance."
Mr Hughes left his West Derby home in January on the 12-month charity mission, which is raising money for WaterAid.
He hopes to raise £1 million on the 56,000-mile trip, which he is documenting on camera for Lonely Planet Television and National Geographic.