A former girlfriend of Connor Betts, the man who went on a shooting rampage outside a bar in Dayton, Ohio, said a number of warning signs led her to break up with the 24-year-old.

Caitlyn “Adelia” Johnson, 24, and Betts briefly dated this spring, NBC reported. She told The (Toledo) Blade the two met in their psychology class at Sinclair Community College. They bonded over their struggles with mental illness; Johnson said she has depression and anxiety, and Betts told her he was bipolar and had obsessive-compulsive disorder. .

At first, Johnson found Betts "kind of charming" and intelligent, The Blade reported. She said he was outgoing and willing to start a conversation with any stranger. Johnson soon learned he had a dark side.

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Johnson said Betts showed her footage of a mass shooting on their very first date. In texts released to The Blade, Betts showed off his knowledge of similar acts of violence.

“Do you know tragedies from every city?” Johnson asked him in the text.

“A fair bit of them! :D (smiley face),” he responded.

Johnson also recalled Betts taking her to a gun range where they used rifles. She said she noticed another red flag when he took her to deliver a threatening letter to the house of his ex-girlfriend. According to The Blade, when Johnson broke up with Betts she asked a friend if she could stay over because she was "scared that he might try to hurt me or stalk me.”

One of Betts' victims was his sister, 22-year-old Megan Betts. Johnson told The Blade that as far as she knew, he liked his sister. She said he never spoke negatively about Megan. But he did have problems with his parents, Johnson said.

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In a video interview with NBC, Johnson said Betts' actions didn't have any sort of racial or religious motive. She said the shooting was probably a result of his mental illness and a lack of treatment.

"People go every day being perfectly fine with having a mental illness, me included, and he just got the short end of the stick,'' she said. "No support system."

More details about Betts have come to light as people who knew him share their recollections and observations of his behavior. Here's what we know: