Authorities are stumped by the sudden disappearance of a man who traveled from India to visit family in Dublin. Police say Siva Kumar Singh-Gadwal walked out of his daughter's apartment in the northwest Columbus suburb on Dec. 11 and hasn't been seen since. Officers have searched by air, used tracking dogs and checked nearby bodies of water. The 56-year-old Singh-Gadwal and his wife arrived from India in early October. His family said he enjoyed walking and often left his daughter's apartment by himself to stroll around the neighborhood.