A Massachusetts Institute of Technology professor has thanked his supporters after the Justice Department said it was dropping its case against him. The department said in a filing Thursday that it could no longer meet its burden of proof in the case against Gang Chen. Chen was accused last year of concealing ties to Beijing while also collecting U.S. dollars for nanotechnology research. Chen's lawyers have said he did nothing wrong. Chen says he will have more to say soon. The dropping of the case is a further setback to an initiative aimed at preventing Beijing from profiting off U.S. academic research.