'John' fears the CIO will come after him following his desertion
"John" - not his real name - is a former agent of Zimbabwe's Central Intelligence Organisation, who claims he fled the country after being forced to kill a man by drowning him in a cement-filled trunk.
He first joined the CIO after being approached at one of the country's notorious National Youth Service Training Camps.
Warning: Readers may find some of the descriptions of torture distressing.
One day, four guys came, driving a black Mercedes-Benz. They put us in a classroom and said they were from the Central Intelligence.
I was afraid, because if you're me, and you don't know about the secret service, all you know is that it protects the sovereignty of your country - it's not a difficult job to do.
I wanted a little bit of income. I said: 'Yes'.
During training, we were told we were going to learn what they called 'torture techniques.'
Everyone was given a cup of gin. We were put into a room with no doors and windows and had to start smoking marijuana.
All of a sudden, a man was put in the room for 'random beating' - where you beat someone haphazardly, no-one really takes charge. You just beat him.
At first the guy was blocking. But we kept on kicking and assaulting him. After he started bleeding, we stopped.
They said: 'Why are you stopping?' So we had to keep on beating him. Then they gave us some pills - I'm not sure what they were, but after I took them I had this rage.
Pliers or screwdrivers
Then another guy was brought in. They said he was a cattle rustler who had been sentenced to 35 years in prison.
'John' was recruited following a period at the National Youth Service
He was put on a desk, and we were given rubber and sticks to beat his feet.
His feet turned black. When we removed him, he couldn't walk. He just fell down and collapsed.
Then a third guy came in. They said this guy had raped and killed a 13-year-old girl. We were told to apply electronic shocking.
We poured some water on him, and then each one of us applied the shock. That was it. By the time we left, he smelled of burnt meat. He just fell down on his face.
The fourth guy, we weren't told why he was brought in. A first aid box was opened - and inside were pliers and screwdrivers. We asked the man to choose between the two.
Our captain attacked his ears with the pliers, pinching a piece out of it. He started bleeding heavily. He then reached into the box, took the sellotape, and put it over the man's mouth so that he couldn't make any noise. You could only see tears.
The captain then took the pliers and called us near. He got near his genitals, then got one of his balls, pressed it with the pliers, and popped it. There was a lot of blood.
Later, we were told to do an operation called 'construction.'
We were told to go to Kariba with a parcel in the trunk of the car. We were not told what was in the parcel, and we were not to open it. We were given some money and drove out.
Then we heard movement in the trunk. There was some kind of a man's voice. We all panicked and tried to look for the keys to open the trunk.
But then we discovered that there was no key. We checked the instructions we had been given, and they said we had to drive to the river - where we would find a speedboat tied to a tree, a bag of cement, and the key to the trunk.
When we got there, we found the speedboat - and there was also a new set of instructions and the key. We opened the trunk before reading the new instructions, and saw there was a man inside.
His hands were cut and he was bleeding heavily. His head was soaked with blood. He couldn't say anything, because his tongue had been cut out.
Many former camp residents say they were trained to torture people
We knew what the envelope would say before we opened it.
I said: 'I'm not doing it.' But Alexander said: 'Look behind you.'
I looked, and there was somebody in the tree wearing camouflage.
So we took the bag of cement and mixed it. Then we started putting it in the trunk.
We tried to shut the trunk, but we could not because the man's head was partially outside.
We put the trunk in the boat. We drove 50 metres into the river. We came back in the boat, without the trunk.
I have a guilty conscience. The things I have done haunt me every day. Every night I cry myself to sleep.
"John" now lives outside Zimbabwe. Parts of his story cannot be verified because of the difficulty of reporting from Zimbabwe.