A Scientist Is Arrested, and Academics Push Back Gang Chen, an M.I.T. professor, faces federal charges of hiding affiliations with China. His colleagues, and M.I.T., are publicly challenging the allegations. Gang Chen, a professor of mechanical engineering at M.I.T., was arrested on suspicion of hiding affiliations with Chinese government institutions in order to secure U.S. federal grants.Credit...M.I.T. CAMBRIDGE, Mass. — It was Donald J. Trump’s last full week in office, so Andrew E. Lelling, the federal prosecutor in Boston, knew he had limited time left in his job. But there was one more important arrest to announce, one that had been in the works for more than a year and would burnish his record on a key initiative of his tenure.