What we know about the gunman who opened fire at a Louisville bank

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.