Wow,I just read the article.
“I never had the opportunity to have a family of my own, I’m terminating yours,” he added.
His Navy career began in April 2002 and ended this month.There's the trigger.
Fits the spree killer profile to a "T".
Spree killings differ from serial killings in that the perpetrator bears a grudge and eventually some incident, sometimes identifiable or sometimes only guessed at, causes him to flip and he immediately commits a killing spree, shooting those he sees as responsible for his predicament, and sometimes randomly shooting and killing people who he sees as representative of those who have failed or rejected him.
Rejection is a common trigger in violence. Sometimes the killing appears spontaneous, but most often it is planned, even if the precise date and time are not.
In most cases, the spree killing ends with the gunman shooting himself or being shot dead by police.