The lack of tangible information about her son Oscar – one of 238 Venezuelans deported by the US to a maximum-security prison in El Salvador – has driven Gertrudis Pineda to despair and left her at the brink of a breakdown.

She bursts into tears the instant we start to talk about Oscar.

“My son only went to seek the American Dream and now he’s trapped in a nightmare,” she sobs.

Oscar lived in Dallas, Texas. Gertrudis explains he laid carpets in apartments for a living: “He helped me by sending money for the family and to buy medicines for his father, who has diabetes.”

Gertrudis is 1,800km away from Oscar, speaking to me from the stifling heat of Zulia state, in western Venezuela.

Mother and son are separated by six borders and the impenetrable walls of the Cecot, El Salvador’s notorious “Terrorism Confinement Centre” – a maximum-security prison built to house violent members of the MS-13 and 18th Street gangs.

The US government accuses the Venezuelans detained at the Cecot of being members of the Tren de Aragua gang.

The Trump Administration removed them from US soil under the 1798 Alien Enemies Act, without due legal process, putting the US Justice Department in conflict with a federal judge who had ordered the planes carrying the migrants to turn around.

Gertrudis knew her son had been picked up by US Immigration and Customs Enforcement (ICE) agents but understood he was in Texas and most likely on his way to Venezuela.

She only found out he had been taken to the Salvadoran prison when her other son, who lives in Colombia, saw his name on a list shown on television.

Soon after, images of the 238 Venezuelans having their heads shaved were broadcast as they were being processed upon their arrival at the maximum-security Cecot.

Gertrudis could make out her son from a tattoo of a rose he has on his forearm.

“There are so many innocent boys in there,” alleges Gertrudis.

“They didn’t do anything wrong but they’re treating them like animals. Where are their human rights?” she implores.

The White House insists those deported to the Cecot were properly vetted. Trump Administration officials say they are all dangerous gang members – even though they have acknowledged in court documents that many do not have US criminal records.

While the Cecot is heralded as the solution to the region’s gang problem by El Salvador’s president, Nayib Bukele, and his supporters, it has long been described by activists as “a black hole of human rights”.

Gertrudis is finding it is also a black hole of information.

She has had no word as to her son’s wellbeing. The last time she saw him, he was shaven-headed, shackled and dressed in a white prison T-shirt and shorts.

She does not know if he is being kept in the same conditions as the Salvadoran prisoners who receive “not one ray of sunlight” as President Bukele put it when he first unveiled the controversial facility with its windowless cells and corridors.

Criticism of the deportation of the Venezuelans to the supermax prison has been growing not just in the US and in their homeland but also in El Salvador.

Salvadoran immigration expert Napoleon Campos thinks the move is unconstitutional and that the constitutional chamber of El Salvador’s Supreme Court “should act”.

“It should declare that bringing these people to El Salvador without them having committed any crime in this country exceeds our constitutional limits.”

He says that “anecdotal evidence” is stacking up that a significant portion of the 238 had no criminal records “not in Venezuela nor in the United States and much less in El Salvador”.

Mr Campos believes the idea of a black hole of rights in El Salvador applies beyond the confines of the Cecot – to the nation as a whole.

“El Salvador today is a deep black hole of illegalities, of violations of the fundamental freedoms and liberties enshrined under our constitution and under the Inter-American Convention on Human Rights,” Mr Campos insists. “There’s no other way to put it.”

The job of negotiating the country’s legal system in the name of the incarcerated Venezuelans has fallen to Jaime Ortega, who says he has been hired by the Venezuelan vice-president to secure their release.

“This case is very sad, and unheard of in our country,” he explains.

“We’ve only seen this in times of slavery, when people were moved between place and place for money. It’s unprecedented.”

He remains confident he can secure the Venezuelans’ release given the lack of clarity over the terms under which they were brought to the Central American nation: “There appears to be some form of agreement between El Salvador and the United States, the documents of which we can’t find, and we don’t have.”

He lays out how if El Salvador had been declared a “safe third country” for immigration purposes, he and others challenging the deportation could work under that clear legal definition. However, that is not the case.

He believes that, at the very least, the men should be placed in some kind of immigration centre ahead of an eventual return to Venezuela rather than in a supermax facility designed for hardened Salvadoran gang members.

President Nayib Bukele meanwhile has roundly rejected all criticism of both the Cecot and his wider crackdown on gangs in El Salvador.

He instead points to the changes his measures have ushered in to Salvadoran society.

It was three years ago this week that he declared a “state of exception” in the country, under which certain constitutional norms and rights have been suspended.

The measure, originally imposed for a month, has now been extended 35 times by a loyalist congress and there is no sign of an end in sight.

The crackdown continues to enjoy overwhelming support among Salvadorans, who re-elected the hugely popular president by a landslide last year.

In part, the reason can be found in neighbourhoods of San Salvador like 10 de Octubre.

Formerly controlled by the MS-13 gang, it was a stronghold of one of El Salvador’s most powerful criminals – Elmer Canales Rivera, aka “Crook”, who is now in prison in the US.

Simply entering the winding collection of backstreets at the base of a jungled hillside was impossible without the gang’s prior approval.

Even with their go-ahead, it would be an unwise move. Extortion, violence and intimidation were rife in this community, whose members were in constant fear for their children, their lives and their livelihoods.

The contrast with the quiet calm of a now-ordinary neighbourhood could not be starker.

Many walls and even trees have been painted bright pink and green, covering the MS-13’s menacing graffiti, and three soldiers stand in the shade holding automatic weapons, a sign of Bukele’s security strategy in action.

“We opened this store after [the state of exception came into force],” explains Roxana, who runs a small shop selling sodas, food and cheap clothes out of her front room.

“Things have changed a lot. We feel calmer having a business and we can stay open late.” The constant demands by gang members for extortion payments have dried up too, she says.

Yet there remains a pervasive culture of silence in former gang neighbourhoods.

Few residents were prepared to give anything more than monosyllabic answers about life under the gangs, and Roxana did not want to give her last name or have her photo taken.

“A lot of innocent people were rounded up too,” she says of President Bukele’s crackdown. “We know of quite a few cases from around here. There are still people in prison who we know shouldn’t be there. It’s unjust.”

At Cecot, thousands of prisoners have been held for years, many without trial. For Oscar, it has only been 13 days, yet for his mother, Gertrudis, it may as well have been a decade.

She is looking after his eight-year-old son in Venezuela as his father languishes in El Salvador.

She says she identifies with the mothers of Salvadorans who are locked up in the Cecot even though they have any discernible gang links, a situation she was unaware of before her own son was detained there with no apparent prior links to the Tren de Aragua gang he is accused of working for.

“My son is Venezuelan, not Salvadoran. So, what that president has done is kidnap our children,” says Gertrudis between heaving sobs.

“If they have carried out any crimes, then they should answer for them here in Venezuela.

“They must send them home.”