MINNEAPOLIS (AP) -

A man convicted of killing his mother and teenage nephew with a sword in Minneapolis has been sentenced to life in prison without parole.

Ishmael Roberts was convicted of two counts of first-degree premeditated murder in the October 2012 deaths of 57-year-old Beatrice Wilson and her 14-year-old grandson, Peter.

The Star Tribune reports police say Roberts, now 25, showed up at his mother's home in the middle of the night and killed the two. A sheath used for a samurai sword was recovered in the home.

Roberts was arrested in Waterloo, Iowa after stealing his mother's car, then crashing it while fleeing from police.