The prison, cut out of the dense jungle that engulfs this island outside Lagos, never officially existed in records, though critics of Nigeria's military rulers were locked up here decades ago in harsh conditions.
Ita Oko Island, accessible only by boat and helicopter, allowed Nigeria's military governments to hold opponents far from public scrutiny in the swamps of Lekki Lagoon. A newspaper expose in 1988 forced officials to close the prison, though local authorities later reopened it for what appears to be a failed $1 million effort to rehabilitate the gang members who dominate Lagos' streets.
As Nigeria plans to open another classified facility to hold and interrogate members of a radical Islamist sect, the Ita Oko Island prison's failed state shows the dangers posed by operating secret prisons and stands as a haunting reminder of past abuses of power that seem quickly forgotten.
"We're in the same situation as far as I am concerned as we were in 20 or 30 years ago, but the scenarios and the narrative are different," said Olisa Agbakoba, a lawyer whose civil rights group helped expose the prison. "We have a rapacious political party in power determined to do everything to retain power and the struggle for power is so intense now that I would not put it past the ruling party to conceal anything to keep it power, including abuses of human rights."
The prison island sits about 100 kilometers (60 miles) outside of Lagos, a rural area where villagers still make a living fishing along the long white sand beaches of the Atlantic Ocean. The 10 square-kilometer (4 square-mile) island is just inland in the lagoon, a wide expanse of water only lightly traveled by locals.
In 1978, then-military ruler Olusegun Obasanjo, who would become the country's elected president, opened the prison he later described as a work farm. But it wasn't until military ruler Muhammadu Buhari, now a perennial presidential candidate, that the prison became a massive holding cell for political prisoners, Agbakoba said.
Under a Buhari decree, anyone deemed by the military government to be a security risk could be imprisoned. Though such sentences were to last only a few months, many saw themselves detained indefinitely in Nigeria's mismanaged prisons.
Those deemed to be a major risk politically found themselves taken to Ita Oko by helicopter, where they worked on the farm and had no contact with the outside world, Agbakoba said. Even today, as the country has become a democracy with the guise of free information laws, it remains unclear how many inmates died on the prison island.
"It was abused by prison authorities," Agbakoba said. "If you misbehave, they said we'll send you as punishment to" the island.
In 1988, the wife of one inmate who discovered her husband had been sent there slipped a note to Nobel laureate Wole Soyinka. Soyinka was on the board of Agbakoba's Civil Liberties Organization, which later traveled to the island with a journalist from The Guardian newspaper who published a story exposing the prison. Authorities quickly closed the prison.
In recent years, Lagos state government said it invested about $1 million to rehabilitate the island into a training center for gang members, known locally as "area boys." But a recent trip to the island by Associated Press journalists found some of the buildings in ruins after what looked like an attack. Fire destroyed some areas, with television sets and other equipment broken on the ground. State government files littered the floor, though a wall clock continued to run on a battery _ suggesting whatever happened occurred recently.
Razor wire and security cameras sat on a 3-meter fence that surrounded what appeared to be dormitories for the site. The main entrance to that area had been padlocked. Someone also left the bones of a small animal on the gate _ a black magic warning to stay away.
Locals from nearby villages said the gang members there had rioted some months ago and escaped. They later came back to free other gang members and destroy more of the property, the locals said.
Lateef Aderemi Ibirogba, the Lagos state commissioner for information and strategy, did not respond to questions from the AP about the facility.
That secret prisons can exist _ and an apparently violent riot can go unreported _ show the ability of Nigeria's government to keep its citizens unaware. The AP has reported that the Nigerian government now is opening a secret detention center for members of the radical Islamist sect known as Boko Haram, which has been blamed for killing more than 520 people this year alone.
Meanwhile, alleged members of the sect arrested in recent months and accused of killing a British and Italian hostage in Sokoto and the Dec. 25 bombing of a Catholic church outside the capital Abuja that killed at least 44 people have yet to appear in a public court hearing. It remains unclear where they are being held.
Associated Press writer Lekan Oyekanmi contributed to this report.
Jon Gambrell can be reached at http://www.twitter.com/jongambrellap.