will be among the mourners on sunday for those who died in the navy yard shooting rampage. this morning we're learning more. kachb travers has more. >> reporter: the pentagon acknowledged there were red flags about aaron alexis. >> why they didn't get picked up. >> reporter: abc news has learned that alexis learned better off this way and my elf weapon on the stock of the shotgun he used in monday's massacre. authorities are trying to determine what those phrases could mean including whether if better off this way meant alexis knew he would not survive his rampage. investigators are also piecing together clues about alexis' mental state. one recent incident stands out. on august 7th at 6:00 a.m. alexis called the newport, rhode island, police. he claimed after an incident at an airport it sent three people to follow him and keep him awake by talking to him and sending vibrations through his body through a microwave machine.