(CNN) -- The mother of the man who gunned down eight of his colleagues at a beer distributor in Connecticut earlier this month says her son was "no monster," but a "gentle spirit" who had reached his limit after being racially harassed at work.
Omar Thornton, 34, called his mother, Lille Holliday, before fatally shooting himself, putting an end to the terrifying shooting spree that left eight people dead at Hartford Distributors in Manchester, Connecticut, on August 3.
"He said, 'I just killed the five most racist people,' and I knew he wasn't playing because he don't talk like that," Holliday told CNN's Soledad O'Brien in an interview that aired Tuesday.
Holliday said when she looked at her caller ID and saw that the phone call was coming from her son's place of employment, "I just kind of lost it."
Manchester police have said they have found no evidence of racial discrimination, and the president of Hartford Distributors said Thornton never filed a claim alleging racial discrimination. Instead, the company said it had asked him to resign after it found him stealing and selling alcoholic beverages.
Holliday disputed that statement in the interview, saying, "I know he reported the [racial] problems because he brought home the papers that they signed."
Thornton's girlfriend, Kristi Hannah, has said Thornton reported seeing drawings of a hangman with a noose around its neck as well as hearing the N-word directed toward him.
Holliday said she had few clues as to what Thornton was planning, but noted, "I could just kind of see slowly he was just getting frustrated and aggravated."
"He was getting more stressed out and he started to just kind of change," Holliday said. "He started not being so relaxed but I never thought that it would be possible that something like this would happen."
Asked about the how calm Thornton sounded when he placed a 911 call to police after the killings, Holliday said, "I think that he was at his limit and the calmness is something that he's always been. I've never really seen him enraged."
Instead, Holliday described her son as a "gentle spirit" who would buy his mother's favorite ice cream and leave it in her freezer or leave a rose for her on her table.
"I wish he was still here with me," she said. "I miss him so much."