MEMPHIS, Tenn. -- A man is behind bars on a $400,000 bond after police say he shot and killed his ex-girlfriend.  Geneva Gladney's son, Derik, says his mother's death is a huge loss for their family, leaving them with so many questions.  University Garden Manor Apartments was once Galdney's home, but now it is filled with tragic memories. MPD: Man kills ex-girlfriend after stealing money from her Memphis Police say 43-year-old Joshua Banks dated Geneva Gladney for about six months before he shot and killed her on Thursday outside her apartment in North Memphis. Joshua Banks (Courtesy of the Shelby County Sheriff's Office) "I was mad. I was hurt. I was in a rage," said Derik. "And I couldn't do nothing for my mom."  As Derik grieves his mother's death, he says he struggles to understand "why."  Investigators say Banks stole $900 from Gladney's bank account, and that's when she ended the relationship. Banks has a history of violence, and the family says he made threats against Gladney and her family after they broke up. 📡 See more breaking news, local news and weather from WREG.com for Memphis and the Mid-South. 📧 Sign up for WREG newsletters and have the latest top stories sent right to your inbox. A relative told investigators that Banks said he would “kill the entire family except for the children,” which left them in fear for their safety. "She loved everybody. She was just full of so much joy and happy to see people doing good in their lives, you know?" said Derik. As Derik's family pushes forward, Banks is now charged with second-degree murder.