Former Palestinian prisoners are speaking out to warn those still held in Israeli jails about a group of undercover informers seeking to trip them up, who are known as "birds."
The network apparently stretches far and wide, with these "birds" tasked with wheedling out confessions that lead to convictions through a mixture of charm, camaraderie and favours.
Often these Palestinians pose as militants jailed for anti-Israeli attacks.
Ahmed Azzam, 30, says his first exposure to the "birds" was after several unsuccessful Israeli attempts at interrogating him.
"When I was 18, I was arrested by the army and charged with setting fire to an Israeli bus. I was interrogated by the security services but did not confess," he said.
"After three days of interrogation I was taken to a room with other Palestinian prisoners, who started talking to me and getting to know me.
"One said he'd shot at Israeli targets, and another said his brother had been killed, so I thought I was in a room full of revolutionaries," Azzam said.
"I mentioned I was craving sweets, and the next day they got me some," he said, noting it was a type that it was not possible to get hold of in prison.
"They treated me well."
And it worked.
"After this treatment and hearing of their heroics against the occupation, I told them what I did and how a friend and I burned the bus."
Three days later, he found himself in court where he was convicted and handed a three-year sentence -- all based on what he had said in the "bird room" although none of it was brought up as evidence due to the secretive nature of the system.
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Fifty-year-old Musa Hassan, had a similar experience 15 years ago when he was taken to one such cell after 10 days of interrogation over his alleged affiliation with a Palestinian militant group.
"When you go into the cell, the men approach you and introduce themselves as members of Fatah or Hamas," he told AFP.
"I already knew about the bird rooms, or 'rooms of shame' as they're also known, so I told them I hadn't done anything and had been wrongly accused," he said.
But based on a confession by another member of his group, Hassan was given a two-year sentence.
Lawyers acknowledge birds are widely used to great effect by Israel, although the evidence gleaned from them rarely comes up directly in court.
"Birds exist in Israeli prisons and are deployed among the prisoners," said Jawad Boulos, legal counsel for the Ramallah-based Prisoners Club.
Israel "doesn't usually use confessions given to the birds in court, but rather uses them to take them into interrogation again and question them about their admissions, and then get official confessions."
The birds' charm offensive, however, is not always guaranteed to get results.
And three months ago, Palestinian officials blamed the far more serious incident of the death of an inmate in detention on the use of "bird rooms" by Israel.
Arafat Jaradat, 30, died very suddenly in an Israeli jail in late February following several days of interrogation over stone throwing, with a Palestinian minister alleging he had been tortured to death, despite Israeli accounts of an apparent heart attack.
But his lawyer Kamil Sabbagh says his death occurred while he was in a bird room.
"It seems that Jaradat was transferred from Jalame detention centre to a special section for birds and died there," he said in a statement.
"There was no acknowledgement he was taken there and no official recognition of the existence of the birds section," Sabbagh said in a separate report on the same incident.
"But the majority of Palestinian prisoners who've been through interrogation have gone there and know it well, and often they confess there," he charged.