AARON ALEXIS

The suspects in the shootings at a Uvalde, Texas, elementary school and a Buffalo, New York, supermarket were both just 18 when authorities say they bought the weapons used in the attacks.

The suspects in the shootings at a Uvalde, Texas, elementary school and a Buffalo, New York, supermarket were both just 18 when authorities say they bought the weapons used in the attacks.

Navy Yard shooter's sister on Aaron Alexis' mental illness Aaron Alexis shot and killed 12 people last year at the Washington Navy Yard. He was eventually shot dead by police, but FBI agents later found a note where Alexis claimed "ultra-low frequency" waves attacked him for months. In an interview only on "CBS This Morning," Vicente Arenas spoke to his sister, Naomi Alexis, who is calling attention to the mental health problems that consumed her brother.