By Lucy Williamson
Palestinian prisoners released from Israeli jails say that guards carried out abuse and collective punishment in the weeks after the Hamas attacks on Israel on 7 October.
They have described being hit with sticks, having muzzled dogs set on them, and their clothes, food and blankets taken away.
One female prisoner has said she was threatened with rape, and that guards twice tear-gassed inmates inside the cells.
The BBC spoke to six people in total, all of whom said they were beaten before leaving jail.
The Palestinian Prisoners Society says some guards are alleged to have urinated on handcuffed prisoners. And that six prisoners have died in Israeli custody in the past seven weeks.
Israel says all its prisoners are detained according to the law.
Eighteen-year-old Mohammed Nazzal was one of those released by Israel this week, in exchange for Israeli women and children held hostage by Hamas in Gaza.
He had been held in custody in Nafha Prison without charge since August, and says he does not know why he was arrested.
Mohammed invited me to his home, down a winding alley in the village of Qabatiya near Jenin, in the north of the occupied West Bank.
The family reception room at the top of the old house was fogged by the smoke of a dozen cigarettes - a cousin circled the visitors with a flask of coffee and a tall tower of tiny paper cups.
Mohammed sat flanked by rows of male relatives, both his hands heavily bandaged, held up in front of him stiffly like a boxer, the tip of his thumbs peeking out.
Ten days ago, he says, Israeli prison guards came into his cell with a microphone and speaker, and tried to provoke the prisoners by clapping and screaming their names.
"When they saw we weren't reacting," he says, "they started to beat us."
"They arranged us so that the elderly prisoners were put in the back and the young in front. They took me and started beating me. I was trying to protect my head, and they were trying to break my legs and my hands."
The family showed us medical reports and X-rays from Palestinian doctors in Ramallah who examined Mohammed after he was released on Monday.
We showed the X-ray pictures to two doctors in the UK, who confirmed that they showed fractures in both hands. It was no surprise to Mohammed.
"In the beginning, I was in a lot of pain," he tells me. "Then after a while, I knew that they were broken, so I stopped using them. I only used them when I went to the toilet."
He says the other prisoners helped him eat, drink and use the bathroom, and that he did not ask the guards for medical help out of fear that he would be beaten again.
The Israel Prison Service has disputed Mohammed's story, saying that he had been examined by a medic before leaving prison, with no medical problem diagnosed.
The prison service also released a video of the teenager leaving prison and boarding a Red Cross bus before his release, which it says proves that his claims are false.
In the footage, the teenager's hands are unbandaged, and appear to be hanging by his sides - including as he climbs onto the bus - but are out of shot for most of the video.
Mohammed told us that the first medical treatment he received was on that Red Cross bus.
A medical report from a hospital in Ramallah the day he arrived back home advised that a plate might have to be fitted, if his fractures did not heal by themselves.
We asked the Red Cross to confirm Mohammed's story. They said in a statement: "We speak directly with the detaining authorities if we have any concerns about the medical condition of detainees. Due to this dialogue, we do not speak publicly about individual cases."
Mohammed says the behaviour of guards inside Israeli jails changed after the Hamas attacks on 7 October.
He says guards kicked them, and used sticks to hit them, and describes one guard stepping on his face.
"They came in with their dogs," he continues. "They let the dogs attack us and then they started beating us."
"They took out mattresses, our clothes, our pillows, and they threw our food on the floor. People were terrified."
He shows me the marks on his back and shoulder that he says were the result of these beatings.
"The dog attacking me wore a muzzle with very sharp edges - his muzzle and claws left marks all over my body," he tells me.
Beatings like this happened twice at Megiddo Prison, he says, and more times than he could count at Nafha Prison.
Other Palestinian prisoners we have spoken to have described a similar shift inside Israel's jails after the Hamas attacks, saying they understood it as "revenge" against Palestinian prisoners for the actions of Hamas.
The head of the Palestinian Prisoners Society, Abdullah al-Zaghary, told us that many prisoners had witnessed cellmates being violently beaten on their faces and bodies, and that he had heard allegations of guards urinating on handcuffed prisoners.
We asked the Israel Prison Service for a response to these allegations. They said all prisoners were detained according to the law and had all the basic rights legally required.
"We are not aware of the claims you described," the statement said. "Nonetheless, prisoners and detainees have the right to file a complaint that will be fully examined by official authorities."
Lama Khater, released from prison earlier this week, published a video on social media alleging that an intelligence officer had "explicitly threatened her with rape" immediately after her arrest in late October.
"I was handcuffed and blindfolded," she told an interviewer in the video. "They threatened to rape me... It was clear the goal was to intimidate me."
Israel said these claims were made by her lawyer and had been denied by the prisoner herself. The prison service had filed a complaint for incitement, it said.
But Lama Khater told us by telephone that women prisoners - including herself - had indeed been threatened with rape, and that tear gas had been used against prisoners in their dormitory at Damon Prison.
The Palestinian Prisoners Society says there has been a sharp rise in the number of Palestinian deaths in custody since the 7 October attacks, with six people dying in jail since that date.
Israel did not address our question about this directly, but said that four prisoners had died on four different dates over the past weeks, and that the prison service had no knowledge of the causes of death.
In Qabatiya village, Mohammed Nazzal says his hands still give him pain, especially at night.
His brother Mutaz told me the teenager he knew before had not returned from jail.
"This is not the Mohammed we know," he said. "He was brave, courageous. Now his heart is broken and filled with terror."
The previous night, he said, the Israeli army had carried out an operation in the city of Jenin, 4km away: "You could see how scared he was."
Additional reporting by Scarlett Barter.
This story was first published by the BBC