Secretary of Homeland Security Kristi Noem confirmed Friday that Claudio Manuel Neves Valente, who authorities identify as the shooter who killed two Brown University students and a MIT professor, entered the U.S. via an immigration lottery system that critics have blasted for years.

“The Brown University shooter, Claudio Manuel Neves Valente, entered the United States through the diversity lottery immigrant visa program (DV1) in 2017 and was granted a green card. This heinous individual should never have been allowed in our country,” Noem said in a tweet.

“In 2017, President Trump fought to end this program, following the devastating NYC truck ramming by an ISIS terrorist, who entered under the DV1 program, and murdered eight people. At President Trump’s direction, I am immediately directing USCIS to pause the DV1 program to ensure no more Americans are harmed by this disastrous program,” Noem continued.

Authorities believe Valente is the individual dressed in black who entered a Brown University classroom December 13 and fired repeatedly into the estimated 60 students in the facility. Two students were killed, including sophomore Ella Cook and freshman Mukhammad Aziz Umursokov, who came to the U.S. as a child from Uzbekistan and became a U.S. citizen in 2011. Cook was from Alabama and served as vice president of the Brown University College Republicans.

After leaving the Brown University crime scene, authorities believe Valente traveled to Brookline, Massachusetts where he entered the home of MIT Professor Nuno Loureiro and shot him. Loureiro succumbed to his wounds a few hours later. Loureiro, like Valente, was originally from Portugal.

The Diversity Lottery Immigrant Visa (DV1) program was launched by then-President George H.W. Bush’s administration, and it has been the focus of frequent criticism for being an entry way for individuals who have no links to the United States. The program, which is administered by the Department of State, provides up to 50,000 visas that are awarded to lottery winners annually.

“The DV Program was established in 1990 ‘to promote immigration from countries underrepresented in the United States,’ and at this point it is a dangerous relic of a bygone age,” according to Andrew Arthur, Resident Fellow in Law and Policy at the Center for Immigration Studies (CIS).

“Most foreign nationals participate in the visa lottery expressly because they have no other ties to the United States — no family and no job here — and to the degree it ever made any sense to put strangers to this country on a path to citizenship through pure blind luck, subsequent threats posed by foreign actors in the interim should have shown how dangerous the program was,” said Arthur, a former immigration judge who is also a former senior staffer for the House Committee on Oversight and Government Reform and the House Judiciary Committee.

Arthur noted that the current tragedy is not the first for the DV1 program. “By the way, you can add to this list of terrorists who exploited the DV lottery Sayfullo Saipov, an Uzbekistan national who ‘plowed into a crowd of bicyclists and pedestrians just blocks away from the World Trade Center’ on Halloween 2017.”

The Saipov attack in New York City prompted CIS Executive Director Mark Krikorian to observe that “from a security standpoint, the program admits a disproportionate share of immigrants from terrorist breeding grounds, and creates new migration networks from those places where none existed before. Looking at the 2015 green card data (the most recent available) shows the lottery accounted for less than 5 percent of total green cards issued that year. But the percentages of green cards from potential terror hotspots that were granted through the visa lottery are much larger.”