Still, he says, he never would have expected the horrific final actions she took.
"Whether it was her or anybody else, it wouldn't be much more of a shock that a mother would murder her children," John Hollis, who hired Sheats as a part-time receptionist for his business, tells PEOPLE. "But the fact that I was connected to her in a sense professionally, looking back on it, I'm more disturbed today than the day I found out."
"Everybody is making an assumption that I 'knew' her," he says. "And in reality nobody 'knew' her, her family didn't know her, nobody knew her, because what she was and the reality of what she presented herself to be were two different things."
Sheats, 42, was shot by police June 24 when she refused to drop her gun after firing and killing her daughters Taylor, 22, and Madison, 17, after convening a family meeting in the midst of tension in their Katy, Texas, home on her husband Jason's 45th birthday.
Hollis owns Clean Canvas Laser Tattoo Removal in Houston, where Sheats was hired for a receptionist position in January 2015. Hollis is the sole other employee of the appointment-only business, where he says Sheats worked no more than 25 hours per week.
He trusted her resume because she claimed "prior salon experience" working in her home state of Alabama. He did not verify that earlier employment before hiring her. "I was going based on her appearance and presentation," he says. "She had that sweet, Southern Alabama look and sound about her."
He says Sheats initially appeared to be a good fit. "She was very pleasant when she wanted to be. That was in front of customers," Hollis says. "The times when she wasn't pleasant were times when I assume that whatever was going on at home was getting to her."
