A man found floating in the Tidal Basin early Thursday was a tourist from the Chicago area who disappeared near the same spot on Easter Sunday, officials said. Sarath Kumar Potharaju, 35, of Grayslake, Ill., went missing the afternoon of March 31 during a tour that stopped at the Franklin Delano Roosevelt Memorial. D.C. police said that it was unclear how he ended up in the water but that there were no signs of trauma. “It’s still a mystery,” said Vijay Kolluru, an uncle who came to the District on Thursday. “We are still wondering how he ended up there,”...