Supermarket mass killer left a chilling prediction about Trump

Police said that a man who killed three of his co-workers in a shooting spree in a northeast Pennsylvania grocery store had a history of posting violent messages on social media, including a chilling prediction about President Donald Trump.

Authorities identified the Twitter account of 24-year-old Randy Stair, who committed suicide after his murder spree. Posting under the name Andrew Blaze, Stair posted this disturbing message about Trump:

The tweet reads, "I can almost certainly guarantee you that Donald Trump will be assassinated. Maybe not this year, but in the near future," and was posted in September of 2016, before the election.

In another post after the election, he wrote, "Donald Trump's face is the *ss of America."

Police said Stair barricaded his fellow employees in a Pennsylvania grocery store and shot three to death. A fourth escaped and called the police. He spent 90 minutes blocking exits, and then began his murderous spree.

"This is really a mental health situation that utterly spiraled out of control," Wyoming County District Attorney Jeff Mitchell said. "I think he had longstanding mental health issues that resulted in this horrible tragedy."

"It's just unspeakable, it really is," he said. "These people went to work and they lost their lives because they went to work. It's senseless."

Stair seemed to obsess over massacres and idolize mass killers on his social media, including Columbine shooters Eric Harris and Dylan Klebold.

In one of the movies Stair left on YouTube, he angrily lashed out at the world, saying, "I've been stepped on my whole life; not anymore. ... I've had enough of this putrid planet and I'm going to leave my mark."

He posted one last tweet before his massacre.