The crash was discovered about 10:45 p.m. Sunday, the Greensburg Daily News reported.
The identities of the victims had not been released, but WISH-TV, Indianapolis, said records showed the single-engine plane was registered to Donald Horan of Greensburg.
Local investigators were working to confirm the cause of the crash, saying fog and a light rain may have contributed to it.
The National Transportation and Safety Board will also be investigating the crash, Greensburg police Detective Bill Meyerrose said.
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