More than 720 men and 11 women are now on death row in Nigerian prisons, and the number is expected to rise. Amnesty International says prisoners are routinely tortured and prison conditions are horrendous. Gilbert da Costa has been speaking to two former death row prisoners and filed this report for VOA.

A presidential commission investigation into Nigeria's justice system found that inmates spent an average of 10-15 years on death row often in deplorable conditions,  many of them suffering from mental disorders.

Food is often insufficient and short on nourishment, the study found. Its says overcrowding in Nigerian jails is leading to violence and disease.

David Lewu spent 14 years on death row in Kaduna prison, in northern Nigeria.

"When you get to the prison, they remove humanity [dignity] from you," he said. "Like even if you have a goat, you cannot keep it in such conditions in the prison. Six by six, you keep four persons. You cannot turn. We call it one man one post. When you are sleeping you can't turn on your own, except you stand up and turn. And they will put a bucket and you will excrete in the bucket-three, four of you, inside a small jungle cell."

Amnesty International and other activists campaigning for death row inmates claim many of those awaiting trial are effectively presumed guilty, even when there is little evidence of their involvement in the crime of which they are accused. The group also found that people not suspected of committing any crime, but rather arrested in place of a family member the police could not locate, are locked up with convicted criminals.

Death row prisoner Dotun Fatiwela was sentenced to death in 1992 and released by the Supreme Court in May 2008 on an appeal.

"One Isa, he was my cell mate," said Fatiwela. "One morning he woke, he said how will he be able to explain; the police just caught him, he can't speak English and they said they saw him pass where somebody had died. And I asked him, didn't they give you time to talk in court? He said I don't understand what they did. 'They just told me go'- and today I'm here. Unfortunately, he died in the prison."

Amnesty International says the Nigerian police routinely tortures prisoners in order to extract confessions.