In 1975, a small restaurant opened called the Bears Brothers' Singing Show. It was revolutionary for the time, still is in a way, the show centered around four animatronics, Blue Bear, Jolly Jack, Reddy Bear and Dopey Dog. When I say the show was centered around them, I mean centered, the animatronics were placed on a revolving stage in the middle of the restaurant. But that wasn't the most revolutionary thing about it, no, it was the fact that the suit themselves were wearable. When a character wasn't on-stage, they were walking around and interacting with people. I imagine this was done to create a greater sense of immersion, to make the characters seem real, but it came at a cost, a great cost.
These suits were expensive, this entire show was incredibly expensive. While it was popular, it wasn't popular enough to keep the business afloat. Sensing that the future was grim for the Bears Brothers, accountant Reed Roberts and technician George Irving split from the company to create their own restaurant.
AWP or Animatronic Workshop & Productions was the company founded by Reed Roberts and George Irving in 1979 with the aim of creating a high-quality animatronic restaurant while still keeping it cost-effective. And, in 1981, AWP opened Flippy's Diner to great success, Flippy's was so successful in-fact that AWP was able to buy what remained of the Bear Brothers' Singing Show by 1983. Flippy's Diner remained popular up until the incident in June 1990, where it closed in the following months.
Reed Roberts was co-founder of AWP along with George Irving (up to a point). It seems he ran the business end of the restaurant while Irving created and maintained the animatronics. Although I don't want to make assumptions about his character, it's good to note that according to those who worked with him, Roberts isn't an entirely reliable narrator, it's said that Roberts frequently downplayed issues in the restaurant and took more credit for things than he should have.
George Irving was the designer and lead inventor of the "Jamboree", the band of animatronic characters at Flippy's: Flippy, Doggy, Swanda and Wolfy, in addition to Mr. Smiley the prize-giving animatronic, and any other miscellaneous characters. It is also said he helped design the decor of the restaurant. Little is known about Irving's character, but it's said that he was a kind, quiet and unassuming guy who was sometimes prone to mood swings and "outbursts". It's also said that Irving had a good relationship with Roberts and his family and was considered a close family friend.
After the incident in June 1990, Irving disappeared and was never seen again.
On the 23rd of June, 1990, George Irving killed five children backstage during a birthday party at Flippy's Diner. He was caught immediately after the act, and somehow fled the building. It is presumed he exited through a window in the restrooms, as he was last seen heading that way. The bodies were found in the "Backdoors", and area behind the stage used for storage and transporting the animatronics between the stage and backstage.
A week prior, on the 14th of June, Roberts' son Daniel disappeared, and was never found. While it can't be 100% confirmed, it is widely believed, even by Roberts himself, that Irving was behind his disappearance.
My father spoke very little of the incident, you'd bring it up to him and he'd just go quiet, not that I blame him. From what I do know, he was there on the day of the incident and witnessed it to some extent. People in town who remember it aren't very willing to talk about it and I've found that mentioning it is a good way to lose a source. Plus, the newspapers from that time are vague about the fine details so I can't really find out much more.