'We couldn't wash. We were harassed. We had no sleep... it was unbearable': The father of '12 Years a Slave' Oscar-winner Lupita Nyong'o speaks for the first time about his own treatment in Kenya

History lesson: Peter Anyang’ Nyong’o, a Kenyan politician

Her performance as the brutalised Patsey in the British film 12 Years a Slave led Lupita Nyong'o to scoop the best supporting actress Oscar, but in real life the Kenyan actress is no stranger to torture and murder.

The body of Lupita's uncle Charles Nyong'o was never recovered after he was attacked on a ferry in Kenya and thrown overboard by regime thugs, and her father was repeatedly tortured because of his opposition to a notoriously brutal former Kenyan regime.

The full horror of her family's treatment at the hands of the then Kenyan President, Daniel arap Moi, only emerged last night when her father, Peter Anyang' Nyong'o, spoke for the first time.

Now a senior Kenyan politician and academic, Peter Nyong'o said: "My brother disappeared in 1980. It was a very difficult time politically. We never recovered his body and it was never resolved who was behind the murder.

"Even now, no information has come to light. I know he was on a ferry in Mombasa and witnesses who I managed to talk to told me clearly that it was not an accident and he had been attacked and pushed off the ferry. But the witnesses were too terrified to testify to the police.... I spoke to members of the Kenyan Special Branch and someone informed me that they knew what happened. They were not willing to help in any way whatsoever because of that."

Peter believes his brother was targeted because of his own student activism, which opposed the Moi regime. He himself was eventually forced to flee to Mexico with his wife Dorothy, where Lupita was born in 1983. It is the reason she bears a Spanish name.

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When the family returned to Kenya in 1987, Peter, who was organising an underground democratic party, was once again the subject of harassment and arrest, with the family forced to hide out at a series of safe houses. "It was a very insecure time. We were moving from one place to another, which was not good for Lupita and Peter Jr." He was regularly detained by the police, and his wife and her family subjected to anonymous threatening calls.

"I was being picked up monthly and weekly. It would depend on the period. It was as often as they wanted. It was mainly psychological for me, although it was physical for others. You could not wash for days, you were harassed, threatened, you couldn't sleep and it becomes unbearable," he said.

He said he found it difficult to watch 12 Years a Slave, but insists his treatment was "like a dinner party" compared to that endured by Solomon Northup. He said: "We were put into prison and the torture chambers by the regime, but it was like a dinner party when you compare it to what the slaves went through."

Nevertheless Peter believes Lupita and his family paid a heavy price. He said: "We were traumatised. The children were too young to understand, and it would not have been advisable to explain because you could be causing them unnecessary trauma."

He believes the constant insecurity and adaptation thrust on Lupita from a young age may have played its part in her being able to take on the chameleon-like qualities needed to be an actor, "although I am wary about generalisations".

As to the film itself, Peter said: "Lupita was very, very captivating. I don't know how she did it. It was a tremendous performance."

Both Peter and his wife were at the Oscars ceremony. "Lupita called me to tell me [when she was] nominated. She was really touched that she had done well enough to be nominated. It was a great achievement in its own right."