MINNEAPOLIS (WCCO) — A man convicted of killing his mother and nephew with a samurai sword will spend the rest of his life in prison.

Beatrice Wilson, 57, and Peter Wilson, 14, were found stabbed to death in their Minneapolis home in October 2012.

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Beatrice Wilson’s son Ishmael Roberts was arrested a day later in Waterloo, Iowa after crashing a stolen car in the city.

The complaint against Ishmael Roberts said he replaced his blood-covered shoes at a Waterloo Target store. Store cameras clearly show him tossing the bloody shoes in a dumpster, along with the car’s blood-covered floor mat.

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Ishmael Roberts was sentenced Wednesday to life in prison without parole.

It’s still unclear why he committed the crimes.

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“We asked him one question — what was this about with your family? He said as is his constitutional right, ‘I don’t want to talk,'” Hennepin County Attorney Mike Freeman said in the immediate aftermath of the crime. “We may never know.”