The schoolboy entered the prison cell crying for his mother. With tears streaming down his cheeks, he pleaded with his fellow prisoners not to hurt him.

“We were trying to reassure him,” says Mohamed el-Maligi, an activist detained in the same cell. “He was asking if we were going to beat him and begging us not to sexually abuse him.”

The boy, a 13-year-old also named Mohamed, said he had been arrested earlier that day in central Cairo while selling pocket tissues to passing drivers.

Detained following the nationwide unrest that erupted after the second anniversary of the Egyptian revolt, Mohamed’s fate is a disturbing example of new tactics employed by the security services.

In the wake of the clashes last month, which left scores of people dead, hundreds of children have been illegally detained by the Egyptian police. Many of them have been beaten, tortured, and sexually humiliated by their captors.

According to Karim Ennarah, a researcher for the Cairo-based Egyptian Initiative for Personal Rights, the rate of child detention over the past month is “unprecedented.”

While the exact number of children arrested is hard to come by—in part because of recent changes to prosecutorial procedures that make it more difficult to track cases—Priyanka Motaparthy, a researcher for Human Rights Watch, tells The Daily Beast that in Cairo and Port Said alone, there have been more than 170 documented cases of child detentions in the last month. And activists, who point out that other cities such as Alexandria, Suez, and Tanta have also experienced unrest, say the problem is nationwide. Mahmoud Bilal, a lawyer who works on the issue, estimates there may be as many as 400 cases from around the country.

Many of the children rounded up during the crackdown have been held in pretrial detention at camps such as Gabal Ahmar, a notorious facility used by Egypt’s central security forces once synonymous with the detention and torture of political activists under toppled tyrant Hosni Mubarak. Such detentions are illegal under Egyptian law, and there have been persistent reports of torture and maltreatment of child detainees. At Gabal Ahmar, the young inmates had been viciously beaten or electrocuted using Taser-style devices, according to Bilal.

“We’ve had reports of police forcing detainees to drink a so-called soup made of salt and water,” he says, and adds that in all the cases he’s worked on, children had been violently attacked following their detention.

There have also been reports of young detainees being sexually humiliated by their captors. At a press conference held by one NGO last week, a 12-year-old boy described how, after being arrested in downtown Cairo, he was stripped naked by a police lieutenant and forced to commit an “indecent act” in front of officers.

Motaparthy from Human Rights Watch said the organization had documented several other instances in which children were stripped by officers and then left naked in their cells.

In addition to reports of institutionalized—and illegal—use of violence and torture against children, the security forces also appear to have been guilty of rank procedural malpractice.

Under Egyptian law, there are clear rules outlining the detention of minors, many of which have been broken consistently over the past month. Numerous testimonies have reached rights workers and lawyers about children under 15 being held in both security camps and police cells prior to trial—a clear contravention of the Child Law, which states that minors cannot be held in police detention.

In a further breach of legislation, Mohamed el-Maligi says he was held in the same cellblock as one 9-year-old boy. There have been numerous other reports of elementary-school-age youngsters being detained in police facilities. In Egypt, it is illegal to hold children younger than 12 alongside adult detainees.

Activists say the cases demonstrate how little President Mohamed Morsi has achieved since being elected last summer. Reform of the notoriously corrupt police service was one of the key demands of the revolt that toppled Mubarak two years ago.

It is still not clear why so many children have ended up in custody. According to Motaparthy, large numbers of detainees are accused of membership in the Black Bloc, an anti-government protest group. But another explanation may lie in the recent behavior of Egypt’s prosecutors.

The prosecution service has been teeming with intrigue in recent months following the appointment of Talaat Ibrahim Abdallah as general prosecutor in November.

Abdullah was hoisted into place via a presidential decree and since then has been accused by critics of deliberately pursing political opponents of the governing Muslim Brotherhood. In December his own prosecutors even staged a rally in Cairo to protest against the perceived politicization of the service.

Some say the new general prosecutor’s zero-tolerance approach has been extended to include children.

Whereas beforehand minors were released relatively quickly following arrest, over the past month, prosecutors have been issuing orders to lock them up for further investigation, often for more than two weeks.

“It’s for political reasons,” says Bilal, the lawyer. “When Mohamed Morsi appointed the new general prosecutor, he chose him because he is loyal to him and won’t object to his laws.”