Homeland security secretary Kristi Noem pauses high-profile visa program, saying shooting suspect Claudio Neves Valente gained green card in 2017

The program makes up to 50,000 green cards available each year to individuals from countries that are underrepresented in the U.S., many of which are in Africa.

Donald Trump suspends green card lottery after Brown University and MIT shooting suspect's entry, citing security concerns and program review.