The Kentucky State Police claimed in a statement that Tyler Wehmeyer, 28, admitted to the killings April 6.
The bodies were found the previous night near Vine Grove, a town southwest of Louisville. Two victims were inside a home, while the third was outside.
A neighbor said Wehmeyer lived at the home.
A KSP report said Doss Smothers, 58, Audrey Whealan, 77 and Michelle Whealan, 51, all died from blunt force trauma.
The Lexington Herald-Leader reported Wehmeyer was related to the victims. But a KSP spokesman did not say how, nor did he give details on what led to the killings.
In addition to the murder counts, Wehmeyer is charged with two counts of cruelty to animals and two counts of evidence tampering. WDRB-TV explained Wehmeyer reportedly admitted moving two of the bodies.
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