A 25-year-old bank employee in Louisville, Kentucky, wrote a note to loved ones before heading to his job Monday morning and opening fire – killing five people and injuring eight others, according to a law enforcement source familiar with the investigation. The gunman, identified as Connor Sturgeon, started his attack around 8:30 a.m. at Old National Bank in downtown, authorities said. He opened fire as some employees met for a morning meeting before the bank was open to the public. Rebecca Buchheit-Sims, a manager at the bank, told CNN she watched the meeting virtually and witnessed her coworkers being slain. Buchheit-Sims described Sturgeon as “extremely intelligent” and others who knew him told CNN they were shocked to see the violence, which launched a massive police response in the heart of one of America’s most populated cities. But prior writings by the gunman indicate he struggled to fit in before he joined the team at Old National Bank. Sturgeon had worked at the bank for more than a year, according to his LinkedIn profile. He livestreamed his attack on Instagram, a video that has since been removed from the platform. A law enforcement source told CNN on Monday that the assailant had been notified that he was going to be fired from the bank. But Louisville’s mayor and police chief have since said otherwise, with Louisville Metro Interim Police Chief Jacquelyn Gwinn-Villaroel telling CNN’s Abby Phillip on Wednesday that that there “was no discussion about this individual being terminated” before the massacre. Gwinn-Villaroel said he did not have “any prior engagement” with police. A search warrant was executed at Sturgeon’s home Monday, Gwinn-Villaroel said in an interview with CNN Tuesday morning, noting she hopes items that were recovered will help shed light on a motive. She did not say whether any other warrants had been executed as part of the investigation. The five victims, all between the ages of 40 and 64, were identified as Joshua Barrick, Juliana Farmer, Tommy Elliott, Deana Eckert and James Tutt, police said. Gov. Andy Beshear said Elliott, a senior vice president at the bank, was one of his closest friends. Eight others were injured, including Nickolas Wilt, a 26-year-old police officer who graduated from the police academy just 10 days ago. Wilt was shot in the head during a confrontation with Sturgeon on Monday morning and was taken to the hospital where he underwent brain surgery, said Gwinn-Villaroel. Shooter wrote a note before attack Sturgeon wrote a note to his parents and a friend indicating that he was going to open fire in the bank, the law enforcement source said. It is not clear whether that note was on paper or emailed, or whether it was seen before the incident or after, according to the source. Sturgeon wrote on his LinkedIn profile that he interned at Old National Bank in Louisville for three consecutive summers between 2018 and 2020 before joining full time in June 2021. Gunman was live streaming during rampage The shooting was live-streamed on Instagram and has since been taken down. Police are in possession of the video, according to the law enforcement source. Earlier on Monday, Gwinn-Villaroel said police were “hopeful” they could get the footage from the livestream taken offline. “I will say this, that the suspect was live streaming. And unfortunately, that’s tragic. To know that that incident was out there and captured,” Gwinn-Villaroel said. Buchheit-Sims, a manager at the bank, told CNN Sturgeon had a “monotone personality. His temperament is pretty low key. I’ve never seen the kid get angry or upset about anything in public. He was pretty much just relaxed.” Buchheit-Sims said she didn’t know anything about the shooter having any grievances or previously making any threats. She recalled him as “extremely intelligent.” Shooter didn’t show red flags, classmate says Sturgeon graduated from the University of Alabama in December 2020, according to a spokesperson for the university. He participated in an accelerated master’s program and earned both his bachelor’s degree and a master’s degree in finance at the same time, the spokesperson, Shane Dorrill, said. Earlier, Sturgeon played basketball and ran track for his high school in a Louisville suburb, and he was named a semifinalist for a National Merit Scholarship in 2015, according to local news reports. A former high school classmate of Sturgeon’s who knew him and his family well said he never saw any “sort of red flag or signal that this could ever happen.” “This is a total shock. He was a really good kid who came from a really good family,” said the classmate, who asked not to be identified and has not spoken with Sturgeon in recent years. “I can’t even say how much this doesn’t make sense. I can’t believe it.” Gunman wrote about difficulty fitting in In a 2018 college essay posted to the website CourseHero, a user identified as a University of Alabama student named Connor Sturgeon wrote that he had had trouble fitting in at school. “My self-esteem has long been a problem for me,” the essay read. “As a late bloomer in middle and high school, I struggled to a certain extent to fit in, and this has given me a somewhat negative self-image that persists today. Making friends has never been especially easy, so I have more experience than most in operating alone.” The author wrote that in college, he had “begun to mature socially and am beginning to see improvement in this area,” and that he hoped to “be more self-aware and start becoming a ‘better’ person.” The gunman’s father, Todd Sturgeon, was head coach of the men’s basketball team at the University of Indianapolis for 10 years and later coached basketball and taught US history at his son’s high school, according to news reports and his LinkedIn profile. A 2007 story published by Todd Sturgeon’s alma mater, DePauw University, quoted an Indianapolis Star article about his retirement from the University of Indianapolis that year, in which he said his son Connor inspired him to step down from the team. “Todd Sturgeon said he was watching his son, Connor, at a basketball camp recently when he had a realization: Maybe he’d rather have more time to spend with his own sons than other people’s,” the article said. This article has been updated with new information from authorities about the gunman’s employment status.