The United States government has suspended its Diversity Immigrant Visa Program, commonly known as the Green Card Lottery, following a recent series of violent incidents allegedly linked to a former beneficiary of the scheme.

The decision was announced after a mass shooting at Brown University last week that left two people dead. The suspect, 48-year-old Portuguese national Claudio Neves Valente, was later found dead in New Hampshire from what authorities believe was a self-inflicted gunshot wound. Investigators say the suspect also killed 47-year-old MIT professor Nuno Loureiro earlier in the week.

According to U.S. officials, Valente entered the country in 2017 through the Diversity Visa Program and subsequently received permanent residency. Homeland Security Secretary Kristi Noem said she has halted the program under the directive of former President Donald Trump, stating the step was taken to ensure “no American has to suffer again because of this dangerous program.”

Authorities say Valente was tracked after a multi-state, six-day search involving public tips and surveillance footage. He was discovered with firearms and other evidence linking him to the shootings.

Brown University confirmed that Valente previously studied there between 2000 and 2001 as a PhD physics student but had no recent affiliation with the institution.

What is the Diversity Visa Program?

Established in the early 1990s, the Diversity Immigrant Visa Program issues up to 50,000 permanent resident visas each year to applicants from countries with historically low immigration rates to the United States. Millions apply annually, and successful candidates are chosen through a lottery system. Applicants must meet educational or work experience requirements and undergo security vetting and interviews.

It remains unclear under which legal authority the suspension will be enforced, as Congress originally created the program and the State Department manages most of its operations, with support from U.S. Citizenship and Immigration Services.

Former President Trump has long criticized the program and previously attempted to end it during his first term, particularly after a separate deadly attack in New York carried out by a past lottery recipient. Supporters of the program argue that it is well-regulated, strengthens the U.S. workforce, and promotes America’s global image.

What Are Green Cards?

Green cards grant eligible immigrants legal permanent residency in the United States and provide a path to citizenship. In a typical year, the U.S. issues close to one million green cards. Around 70% go to individuals with family ties in the country, while most employment-based green cards are granted to migrants already living in the U.S. under temporary visas.

Further clarifications on the duration and legal standing of the suspension are expected in the coming days.