the days before the shooting. >> abc has more from the navy yard. karen? >> reporter: we started to hear more details about what happened here at the navy yard on monday and how aaron alexis got into building 197 and started that rampage. the fbi said they are still trying to determine a motive. what made aaron alexis go on a killing rampage. authorities say his deteriorating mental health may have been a factor. abc news learned in early august he was kicked out of a military housing complex after he complained of too much noise coming from a linen closet. a federal law enforcement official said it is unclear if the navy followed up. around that time, alexis allegedly had a run-in with a family at the airport in norfolk. glenda boyd told abc news she was there with her family when her 75-year-old aunt laughed loudly at a joke. out of nowhere, a man that looked like alexis confronted him.