The person of interest taken into custody Sunday in connection to the deadly mass shooting at Brown University has been identified as Benjamin Erickson, law-enforcement sources told The Post. Erickson, 24, was nabbed at a local hotel room after a gunman opened fire at the Ivy League institution’s Providence, RI, campus during a final-exam study session Saturday. The shooter was armed with a handgun and fired more than 40 .9mm rounds during the chaos, law-enforcement officials said.