MINNEAPOLIS (WCCO) — St. Paul police say a 24-year-old man is in custody after fatally stabbing his younger brother.

The St. Paul Police Department says the stabbing happened early Tuesday morning on the 2200 block of Lower Afton Road.

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The older brother was arrested, questioned and booked into the Ramsey County Jail. It’s currently unknown what the brothers were fighting over, investigators say.

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This teenager’s death marks the 20th homicide in St. Paul this year.

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The stabbing comes following a night of violence in the Twin Cities, where shootings killed two people in south Minneapolis and a domestic situation left two more dead in Blaine.