Next tonight we bring you word of another red flag about the mental health of the shooter at the washington navy yard. A recent bizarre encounter, a mother and her family are coming forward to say... See More
Next tonight we bring you word of another red flag about the mental health of the shooter at the washington navy yard. A recent bizarre encounter, a mother and her family are coming forward to say that well before the shooting aaron alexis was giving clear signals something was wrong. Abc's senior justice correspondent pierre thomas has it. Reporter: When glynda boyd first saw the horrible images of the navy yard massacre and then the face of the killer she was stunned. What we're learning about the gunman. I started to scream oh, my god that's him and I just started screaming. Reporter: The memories of an unsettling encounter of paranoia came racing back. We were eye to eye. Boyd and her family were on their way home from a family reunion on august 4th when the man she believes is aaron alexis came out of nowhere. He kept saying is she laughing at me? Is she, you know, we were like, no. Then he just got angry. Reporter: The look on his face is etched in boyd's mind. I felt fear, a sense of fear, something wasn't right with him mentally. Reporter: Airport security intervened but no one was charged. Abc news confirmed alexis was at the airport. It was only three days later that alexis would call newport rhode island police with a bizarre story about hearing voices and being under surveillance after an altercation at a virginia airport. Some of these people who really are suffering from a mental health problem or issue really have nowhere to go. Reporter: Today we learned how alexis got a shotgun past security at the nayy yard. The director james comey told us alexis sawed off his shut gun apparently so he could hide it in a bag. He was hunting victims, randomly shooting anyone he encountered. Pierre thomas, abc news, washington.
This transcript has been automatically generated and may not be 100% accurate.