By Mariam Omar
BBC Swahili Service
Homosexual rape is rife in prisons in Kenya and Zanzibar.
Officials deny that rape is occurring
For the first time, victims talk about their experiences in a shocking indictment of neglect and violence.
It is a nightmare for anyone, anywhere, to find themselves in a police car on their way to prison.
But many think that in jail there is protection around the clock, not knowing that prison may be more dangerous than the life they left behind.
One man told me he was raped within hours of the gates closing behind him at Kamiti Maximum Security Prison, where he was jailed for five years for robbery.
"They were fighting over me, they were fighting over who should get me first," he said.
"I just had to wait until the fight was won and then be raped by the winners."
Another young man, too ashamed to want his name revealed, was jailed for three years for the theft of a bicycle.
It was his first offence and within hours he had been gang raped.
"They took me to a cell - they were huge people and I was very little and young," he said.
"They invited me to share their supper. I agreed, thinking they were good people. I did not know they had put sleeping pills in the food.
"After supper, I went into a very deep sleep. I was unconscious. That's what they wanted - that's when they raped me."
I found this kind of story to be commonplace.
Male rape happens in many prisons around the world. What makes it different in East Africa is that attitudes to homosexuality in society generally mean that this terrible problem is never acknowledged, never spoken about, even by the victims.
It is denied by officials - and by society at large.
The deputy officer in charge of Kamiti Prison, Pite Nguguna, told me there was no abuse at all there.
"We don't have rape in prisons," he said.
"We have never had a rape case reported while prisoners are serving their jail terms.
"Maybe there was an encounter with somebody, maybe, who was homosexual.
"But homosexuality itself is a very secretive kind of activity, so for the authorities it's not known to us."
So, plenty of proof on one side, and plenty of denial on the other.
Given that most African cultures do not entertain homosexuality, what else encourages rape in these African male prisons?
"Prisoners are just human beings," said Emmanuel Wetangula, a lawyer in one of Kenya's leading law firms.
"They do have sexual needs which they have to attend to. They do not get conjugal visits from their wives or girlfriends."
Mr Wetangula knows the structure of prisons facilities in Kenya, and he is of the opinion that congestion in the prisons might be one of the reasons for the increase of rape in male prisons - since the warders cannot get proper access to all the cells in the prison.
He explained that the biggest problem is that prison conditions have various categories and cartels.
So when a new prisoner arrives, he is actually seen to be different from the rest of the prisoners - and deemed "fresh."
"It commonly happens among the newcomers, the new entrants into prison," he added.
I managed to get hold of Chena, who is a prison leader in a Zanzibar prison, and who has been in and out of jail several times for robbery.
He told me that there were a number of reasons why rape goes on.
"Sometimes it might be lust - plain sexual gratification," he said.
"Sometimes the person wants to show power, to have power over another prisoner. Sometimes by raping a fellow prisoner, that person can make even the warders fear them."
He added that this was the case with himself - although he denies he has actually been a rapist himself.
"They fear me," he said.
"I might look small to you, but I am strong - very strong. I fear nobody.
"I can rape, I can do whatever I want to anybody, and no-one will dare question me.
"That is power."