WASHINGTON - Police have charged a white University of Maryland student with the on-campus stabbing death of a newly commissioned black US Army lieutenant, and the FBI is investigating the case as a possible hate crime, authorities said on Sunday.The suspect, Sean Urbanski, of Severna Park, Maryland, is facing a first-degree murder charge in the stabbing death of Second Lieutenant Richard Collins III, 23, early on Saturday, University of Maryland Police Chief David Mitchell said.Urbanski, 22, approached Collins and two friends on a campus sidewalk and told Collins, who was commissioned as an officer on Thursday, "Step left, step left if you know what's good for you," Mitchell said.When a puzzled Collins said, "No," Urbanski stabbed him in the chest, the police chief told a news conference. Collins, who was to graduate from Maryland's Bowie State University on Tuesday, was pronounced dead at a hospital, he said.An investigation showed that Urbanski was part of the Alt-Reich Facebook group, which carries racially and sexually charged material, and triggered a probe into whether Collins' death was a hate crime, Mitchell said.The Facebook site "is despicable. It shows extreme bias against women, Latinos, members of the Jewish faith, and especially African-Americans," he said.Gordon Johnson, the special agent in charge of the Federal Bureau of Investigation's field office in Baltimore, said: "We are here to evaluate that, as an ongoing concern with respect to whether or not this was a hate crime."Police arrested Urbanski on the campus, which is in College Park, Maryland, Washington suburb. He also is charged with second-degree murder and first-degree assault.