Updated at 4:27 p.m. ET
It took less than 24 hours after Tuesday's terrorist attack in New York for the finger-pointing to begin.
And the first fingers are being aimed at what had been an obscure State Department immigration program called diversity visas.
The Department of Homeland Security confirmed that the accused terrorist, Sayfullo Saipov, entered the U.S. with such a visa, after winning a yearly lottery in which up to 50,000 foreigners are awarded green cards.