"I'm starting to see why plp go on killin sprees"

On August 31, 2012, 23-year-old Terence Tyler checked in for the overnight shift at the Pathmark Super Center in Old Bridge, New Jersey. His co-workers noticed that he was acting "very angry," and before long, he simply walked out and left work altogether.

But he would come back shortly, armed with three firearms. Tyler then opened fire, killing two of his co-workers, Cristina LoBrutto, age 18, and Bryan Breen, age 24, before taking his own life with a gunshot.

Between June 2010 and November 2011, Tyler purchased the weapons used in the shooting legally: a shotgun, a .45-caliber handgun, and a WASR-10, which is similar to an AK-47 assault weapon. Those purchases likely occurred in California, before Tyler moved to New Jersey.

Sometimes after gruesome shootings, profilers of the killers in question will suggest that "no one could have seen it coming." But that certainly wasn't the case with Terence Tyler.

Tyler had served in the U.S. Marines for four years before being honorably discharged in 2010 for medical reasons. That reason was "major depression." This depression was well known to Tyler's family, and began after the death of his mother in 2007.

And then there was Tyler's Twitter account, through which he posted the following public messages (most recent at top, going chronologically backwards as you scroll down):