Police link man in fatal grocery store shooting to Twitter account

— -- Authorities in Pennsylvania have confirmed today that the "Andrew Blaze" (@EGSAndrew) Twitter account belongs to the man who fatally shot three grocery store coworkers in Wyoming County this week, before turning the gun on himself.

Randy Robert Stair, 24, of Dallas, Pennsylvania, is believed by authorities to have created "different alter egos" in social media and his various accounts may have been following one another, according to Jeff Mitchell, the county's district attorney.

Mitchell also said that Stair had posted a tremendous amount of information online -- journals and videos -- documenting troubling thoughts and plans. Authorities said social media posts included videos of Stair firing and brandishing weapons as well as praising the Columbine killers. One video described his plans for the grocery store massacre in intricate detail.

"This is an individual who was deeply disturbed," Mitchell said. "We need to figure out how and why this happened."

Pennsylvania grocery store employee kills 3 coworkers, then himself, police say

Despite Stair's posts on Twitter and on YouTube, Mitchell said authorities had so far learned of no one who had raised a red flag, had responded to any posts trying to talk Stair out of anything or had warned anyone about his plot. However, according to The Associated Press, a 42-minute film about a violent massacre was posted by Stair, Mitchell said, about the time of the killings.

Around 12:50 a.m. Thursday, Stair pulled two shotguns from a duffel bag and fatally shot three co-workers at Weis Markets, police said. He'd been working an overnight shift since 11 p.m. Wednesday. Mitchell said today that Stair also shot up the store, firing "almost 60 shots."

Police said he fatally shot himself in the head. The store was closed to the public at the time of the shooting. One coworker managed to escape the store and called 911, police said. No one else was found inside.

"I'm grieving because these are my friends. I've been around them forever. This is the saddest thing I could ever imagine, something like this happening here," friend Tracy Klepacz told ABC affiliate WNEP-TV.

The victims were identified as Terry Lee Sterling, 63; Victoria Todd Brong, 26; and Brian Hayes, 47, police said.

Autopsies were conducted this morning. The investigation continued both at the scene and online.