Because there have been no arrests and the sheriffs department has not shared any concrete leads, Thompson worries that the killer may still be in the community.
"I've thought, 'Please don't let it be one of these people that's come around and hugged me and said how sorry they were.' I've thought, 'I wonder -- when we were doing the candlelight vigils if -- if he was out there," she said.
And if it turns out to be someone she knew?
"God have mercy on their soul. And they better be lucky that the Clay County Sheriff's Office is gonna get to 'em before I can."
It is a struggle to balance that anger with a mother's need to stay strong for her remaining children. Thompson said the ordeal has been especially hard on Somer's twin, Samuel.
They used to play in the pool together and race each other to see who could stay underwater the longest.
"We used to nickname her 'Grace' because she couldn't really walk and chew bubblegum at the same time," Thompson said of Somer.
She loved to dance, but she had no rhythm, Thompson said.
"She was just so wonderful. And you take it for granted. You never think you're gonna be sitting here," Thompson said. "And you have a lot of regret because you may have been too busy. And you weren't really busy. You were just too busy in your head. And I'll have to live with that, and that's hard."
She said she would tell other parents to be sure and tell their children they love them every day.
"It don't take but a couple seconds. And when you think you're too busy, really think about what you're saying you're too busy for. Because you don't want to live with this. That's what I regret. It's hard to live with regret and guilt," she said.
Diena understands acutely that the world's attention will move on. The flowers in her home are beginning to fade. The vigils that used to occur nightly have grown more infrequent.
But she is determined to continue the fight for justice.
"I know I'm not gonna let this monster win. I will be victorious in the end, and he will pay," she said. "We're gonna get him, and he will pay. And I hope he's scared."
Visit www.rememberingsomer.com for more information on the reward fund and family relief fund.
Police have asked that if you have any information about this case, contact the Clay County Sheriffs Department in Jacksonville, Fla. at (877) 227 - 6911 or the FBI.