Henry Okah is charged with treason and gun running
The Nigerian government has denied it tried to kill a prominent leader of an oil militant group with a snake in his detention cell.
The Movement for the Emancipation of the Niger Delta (Mend) sent an email to journalists alleging Henry Okah had twice had to kill snakes in his cell.
A spokesman for the military denied the claim and said it was "ridiculous".
Mr Okah has been charged with treason over his involvement with militants in the oil-rich Niger Delta region.
He faces the death penalty.
"A very reliable security source informed us that a large poisonous snake was discovered and killed by Henry Okah inside his dungeon at the Army Directorate of Military Intelligence today," the email from Mend spokesman Jomo Gbomo said.
But Mohammed Yusuf, spokesman for the Military denied the claim.
"That's a wonderful story, but its totally untrue. So what now? Every time someone gets bitten by a snake its the military's fault? There is no truth to this story. How could a snake get into his cell?" he said.
When asked why the military would need to use such a bizarre method to kill Mr Okah, Jomo Gbomo said not everything the government did had to make sense.
"We are not trying to figure out why the snakes have found their way there but to pass the information to the world. Many things Mobutu, Idi Amin, Mugabe and a host of African leaders have not made sense," Mr Gbomo said.
The BBC's Andrew Walker in Abuja says Mend has a very slick media operation, and the release may be an attempt to get some free publicity.
It is impossible to independently verify the story.
After Mr Okah was extradited from Angola in February they released a statement saying he had been killed by security forces. That claim later turned out to be untrue, but it brought his case into the media spotlight.
Mr Okah was arrested in Angola in September. The government says he was trying to buy arms, but his lawyer says he was trying to buy a second-hand trawler.