Surrounded by glittering waters, Rwanda's remote Iwawa island appears idyllic, but it has housed thousands of drug users, as well as reputedly those the government deems unsuitable for society.
Isaac Mugange was an alcoholic and heavy smoker of cannabis, but the 24-year computer technician was sent to the Iwawa Rehabilitation and Vocational Training Centre, a tiny island in the vast waters of Lake Kivu, to wean himself off drugs.
"A family council decided to send me here to rehabilitation, and I agreed," said the young man, who comes from a wealthy background. His large eyes are still reddened by years of abuse.
The jungle-clad island ringed by beaches could appear at times like a holiday camp. But it has a darker reputation: on the mainland, Iwawa is spoken of by some as a "Guantanamo" or "Alcatraz", a reference to the infamous US prisons.
Critics say Iwawa, officially set up to help drug addicts, also houses beggars, homeless people, street children and petty criminals — or anyone who might taint the clean image Rwanda seeks to promote.
Rwanda's tough leaders have sought to rebuild a society left in ruins after the 1994 genocide, pouring energy into creating an orderly nation with smooth roads, efficient administration and tight security — efforts that critics say can also go too far, suppressing dissent.
Like nearly 2,000 others aged between 18 and 35, Mugange spent a year on the island some 28 kilometres from the mainland of south-western Rwanda. After six months attending sessions with a psychologist, he is now learning carpentry.
Rwandan authorities insist it is a drug detox and rehabilitation centre, not a detention island or prison.
"This centre is a training school that helps youths, first to get rid of drugs, but also to develop professional skills that can help them earn a living... and become a solution for the government rather than a burden," said Servilien Bizimana, deputy director of the centre.
In a workshop nearby, Mugange and 20 companions cut and sand down wood. Behind a basketball court, dozens of youths sitting under shade trees listen to lessons on hygiene. Others wait at the health centre to be circumcised, as part of a government program aimed to reduce the risk of AIDS. The centre's leaders insist all residents are on the island voluntarily.
While the government "reserves the right to help the addicts" by sending them to Iwawa, centre coordinator Nicolas Niyongabo said they are all still free to leave the island if they wish.
But in Rwanda's capital Kigali, one former resident insists that several escape attempts resulted in drowning. The centre's management says two people drowned due to swimming accidents in 2013.
On the island, Olivier, a man in his 30s, admits to being a drug addict and alcoholic. "I was arrested by police in Kigali. I was drunk and I didn't have my papers," he said, sitting at a sewing machine. "I want so much to go to Kigali... my wife does not know where I have been for the past five months, because I do not know the phone number."
Centre residents are allowed to make telephone calls and receive visits, but many families are not informed when their relatives are sent to the island, often on simple administrative orders without legal processes.
Rwandan Justice Minister Johnston Busingye said courts were not needed "to make that kind of decision", but doctors and psychologists on the basis of risk and the chance of rehabilitation.
Jean-Claude Rushinga, 24, has spent five months on the island. He denies being an addict, claiming instead to have been a unlicensed street hawker selling clothes. "I was selling clothes and the police caught me," he said, adding philosophically he had since accepted his exile.
"I said to myself, for once in my life after all, I am going to learn something." But Niyongabo insists the man is in denial.
"The state spends a lot of money each year on the centre" for drug addicts, and does not deal with simple street vendors, he said. Nonetheless Rwanda has admitted that last year it sent more then 280 alleged army deserters to be "re-educated" at the site.
Security on the island is provided by the army, although no soldier was seen during the visit by AFP. The management denies any mistreatment of residents. But in Kigali, several former residents complained of severe military-style discipline and corporal punishment.
"There was terrible punishments — caning, walking in a crouched position, you lie on the ground and water is poured on you," a former resident told AFP, asking not to be named.
"I think it is good that the Iwawa centre exists, but it should reduce the punishment," the young man said, who added that he believes his stay enabled him to stop drugs and resume his studies.