The draconian mass incarceration policy of El Salvador’s president, Nayib Bukele, may have led to crimes against humanity, according to a new study by legal experts.

By locking up 1.4% of the population without due process, Bukele turned El Salvador from one of Latin America’s most violent countries into one of its least violent – but at the cost of human rights and the rule of law.

The report, compiled by an international group of experts assembled by the Due Process of Law Foundation, documents the arbitrary imprisonment, torture, murder and forced disappearances that have taken place under the state of exception that began four years ago, describing them as “the result of a policy known and promoted by the highest levels of government”.

Given these widespread and systematic attacks on the civilian population, the authors conclude there are “reasonable grounds” to believe that crimes against humanity are being committed, urging the United Nations to create an international mission to investigate.

“The state must protect citizens from organised crime – but with the law, and with respect for human rights,” said Santiago Canton, co-author of the report and general secretary of the International Commission of Jurists.

El Salvador has been in a state of exception since 2022, when Bukele suspended constitutional rights and unleashed security forces to take on MS-13 and Barrio 18, the gangs that brutalised Salvadorian society for decades.

Roughly 90,000 people have been arrested since. Most are being held in pre-trial detention, in grim conditions. Human rights organisations believe thousands without any ties to gangs have been swept up and have documented more than 400 deaths in custody.

Many are in the Terrorism Confinement Centre (Cecot), a showpiece mega-prison built by Bukele specifically for gang members – and also where the Trump administration paid to hold more than 252 Venezuelan migrants it expelled, who have since spoken of the abuse and torture they faced before being sent back to Venezuela as part of a prisoner swap.

Bukele’s mass arrests broke the gangs’ territorial grip, brought homicides down and gave most Salvadorians a kind of freedom they hadn’t known for years. In 2024, they voted to give him an unconstitutional second consecutive term.

The “Bukele model” and its promise of security and popularity has won him admirers among leaders in Latin America and beyond.

“It has had a huge impact,” said Canton. “Governments – mostly the new right that we are seeing, but also some from the left – are using it as an example. Go to any country that has elections and Bukele is there on the streets.”

In Chile, the incoming president, José Antonio Kast, recently described El Salvador as “a lighthouse in a world roiled by organised crime”.

But Bukele has at the same time dismantled checks and balances on his power, firing judges who oppose him, changing the electoral system in his favour, and persecuting critics in civil society and the press, many of whom are now in exile.

That includes Cristosal, a leading human rights organisation in Central America, which fled to Guatemala last July after its chief anti-corruption investigator, Ruth López, was arrested.

Almost a year later, López remains in prison – along with another 85 political prisoners, according to Cristosal.

Meanwhile, El Salvador’s congress, which is almost entirely dominated by Bukele’s party, has scrapped presidential term limits, paving the way for Bukele to seek indefinite re-election.

“It took us decades to build democracy in all these countries,” said Canton. “And the Bukele model that these Latin American politicians are lauding ultimately implies its destruction.”