During his senior year of high school, Connor Betts seemed to always have caffeine pills in one hand and an energy drink in another. He was unable to sleep, he told his then-girlfriend Lyndsi Doll, because of dark, animal-like shadows that tormented him at night.
Seven years after they dated, Doll recalls Betts as a serious and reserved kid who wrestled with hallucinations and menacing voices in his head.
While they were in high school, Betts told Doll that he had suffered from psychosis since he was young and feared developing schizophrenia.
"He would cry to me sometimes," she said, "saying how he's afraid of himself and afraid he was going to hurt someone one day. It's haunting now".
Wearing body armor and a mask, Betts opened fire with an AR-15-style pistol outside a bar in Dayton, Ohio, early Sunday, killing nine people. The massacre, which left at least two dozen others injured, lasted less than 30 seconds before police shot and killed the 24-year-old.
What was his intention?
Among those killed was Betts's younger sister, Megan. Dayton Police Chief Richard Biehl said Monday that authorities may never know whether Connor Betts intended to kill his 22-year-old sibling.
"It just seems to defy believability that he would shoot his own sister," Biehl said. "But it is also hard to believe he didn't recognise his sister, so we just don't know."
Doll said she liked Betts most when he was with his sister, describing them as close friends. She remembers him speaking highly of Megan, of her intellect and kindness. They would gently tease each other and often erupt in fits of laughter when together.
"They would play off of one another," she said. "She was the bright, happy soul and he was the dark, more reserved one."
But Doll said she always knew that something was "off" about Betts. When she enrolled at Bellbrook High School her sophomore year, she heard stories about a "hit list" that Betts had compiled with names of people he wanted to kill. As she got to know him, her friends grew wary and warned her of Betts's tumultuous past relationships. They told her he had pushed one ex-girlfriend into a roaring river and had screamed at another while pinning her against a wall.
But Doll grew to trust Betts as they hung out in the same circle of friends, and she soon found herself drawn to his quiet charisma.
"He was funny, he was charismatic in his own way," she said. "In school at least, it was always just Connor being Connor."
They connected over their shared mental health struggles - she suffered from anxiety and depression - often turning to each other for support.
But as their relationship progressed, Doll became increasingly concerned that Betts was far from normal and desperately in need of professional help. He talked a lot about the "dark, evil things" he heard in his head. He would sometimes check out midway through the conservation, when it seemed like his mind would drift elsewhere.
Biehl, the police chief, said Betts could have been carrying 250 bullets when he began his rampage in Dayton's Oregon district, the maximum capacity of the magazines he was carrying. Betts carried a pistol modeled on the AR-15 that fires rifle rounds. He used a 100-round capacity drum, allowing him to fire many rounds without reloading.
Fourteen people suffered gunshot wounds, while others were injured when they were trampled or hit by flying glass as they ran for safety, according to Biehl.
41rounds fired by Connor Betts, based on recovered shell casings, on the fatal day.
Based on recovered shell casings, he said Betts fired at least 41 rounds before police officers responded, shooting 58 rounds at him near the entrance to a Dayton nightclub.
Dayton police spokeswoman Cara Zinski-Neace said Monday that Betts had modified his weapon so he could stabilize it on his shoulder while firing. Betts had a "pistol version" of an AR-15-style rifle, she said, not designed to be shouldered. But Betts added a brace.
"It is fundamentally problematic to have that level of weaponry in a civilian environment, unregulated," Biehl said, adding that the gun appears to have been purchased on the Internet and then modified "to avoid any legal prohibitions."
Betts had travelled to the area with Megan and her male companion, parking a few blocks from Ned Peppers Bar. At some point, Betts left the group and later opened fire, carrying extra ammunition in a backpack. The man who traveled there with him and his sister was shot in the lower torso and remains hospitalized.
Biehl said he has no information to suggest that Megan or her male companion were aware that Betts had brought the weapons with him in the trunk of the vehicle.
Speaking at a news conference, Biehl said authorities are still investigating a possible motive for the shooting but have no reason to suspect the crime was racially motivated. Betts was white, and most of those killed were black.
He had a 'hit list'
Biehl said that the male companion is cooperating with authorities but that officials don't know the exact nature of his relationship with Megan.
Betts was raised in Bellbrook, a suburb southeast of Dayton. Several former classmates at Bellbrook High School said he was interested in guns and frequently harassed female students.
Midway through Betts's freshman year, school officials became aware of a "hit list" of people he wanted to take revenge on, according to classmates, who said police took him from the school bus one day. He was absent from school for months afterward, they said.
Sugarcreek Township police declined to comment, except to note that juvenile records are sealed when a subject reaches age 23.
Biehl said he is aware of media reports about the suspected hit list, but he cautioned that the alleged incident occurred a decade ago.
"We are clearly exploring every possible piece of information," Biehl said on Monday. "I am a little bit reluctant, even if there is such evidence, to interpret it 10 years later, that it is indicative of what happened yesterday."
A former friend of Betts, who spoke on the condition of anonymity to maintain her privacy, said she and Betts's group of friends had a reputation at Bellbrook as "the emo kids, the outcast kids that the cool kids didn't really like." The group of about a half-dozen people dressed in dark clothing, including Betts, she said.
On weekends, the friends would sometimes smoke marijuana or drink alcohol, she said, but most often, they just "hung out and chilled," making idle conversation.
That was when Betts would meditate on "death and dark, morbid stuff," she said. He also told at least one member of the group that he sometimes heard disembodied voices.
Betts also liked to talk about politics, the friend said. He registered as a Democrat in 2012, and in high school he would frequently trash Republicans, she said.
A now-suspended Twitter feed - which included several selfies of Betts and his family, and referenced growing up in the Dayton area - suggests far-left political beliefs, concern over climate change and a penchant for violent jokes.
The Washington Post captured more than 3,000 tweets on the account, which was created in December 2013 and used the handle @iamthespookster. The owner was an avid and frequent user of the social media site - before the account was suspended late Sunday night. A Twitter spokesperson said that the company removes all "content that violates our policies and will be engaged with law enforcement, as appropriate" but declined to elaborate further.
In addition to occasional selfies and pictures of a Betts family dog, the user often tweeted in support of policies and programmes associated with far-left American politics.
The user also retweeted posts criticising capitalism, and at least once retweeted an item jokingly calling for the "beheading" of oil executives as a way to combat climate change. A retweeted post that suggested that people who order a "Twix Frappuccino" or a "Strawberry Cheesecake"-flavored drink from Starbucks should be choked by the barista was also on the account, as well as a picture of Gandalf - photoshopped to make the wizard cradle a rifle - along with the caption "swords are no more use here."
The user also retweeted a post that, along with images of news stories about the resumption of capital punishment in the United States, among other things, instructed users of the social media site to "buy a gun and learn to use it responsibly" because "you may need to protect yourself."
A few days before the shooting, the user was riled up about the Equifax data breach and retweeted a July 29 post reading: "Losing your personal information in a massive data breach is just a thing that happens now, like 110 degree days and regular mass shootings."