Arron Lewis and his estranged wife, Crystal Lowery, deny killing the Arkansas Realtor
Credit: Pulaski County Sheriff's Office

When realtor Beverly Carter vanished on Sept. 25 while showing a house to a prospective buyer, the community of Scott, Arkansas, hoped for her safe return.

Police quickly focused on 33-year-old Arron Lewis as their suspect, and they say he led them to her body five days later. He was arrested. A month later, his estranged wife, Crystal Lowery, was also arrested and charged with the murder.

Lewis initially told reporters that he had targeted Carter because “she was just a woman who worked alone – a rich broker.” But in court on Thursday, he and Lowery both pleaded not guilty to the killing. According to defense attorney James Hensley, Jr., the defense team wanted Lewis to undergo a mental evaluation, but he rejected the request.

During the hearing, Lewis requested permission to send letters to Lowery from prison. He has apparently been sending letters since she was arrested, but felt that the letters weren’t going through. As he was escorted out of the courtroom, Lewis spoke briefly to the assembled reporters. “This is getting ridiculous,” he said. “I just can’t talk to her.”

The proceedings have been difficult for Carter’s tightly knit family to sit through. Her son, Carl, was in the courtroom during the pleas. “It was surprisingly hard to be in the same room,” he tells PEOPLE.

To keep his mother’s memory alive, Carter is hosting an event next February to raise awareness about safety and crimes against women. Participants will wear hot pink “Remember Beverly” shirts in her honor and run the Little Rock Marathon 5K to raise money for the Joyful Heart Foundation, a charity founded by Mariska Hargitay to combat domestic violence and sexual assault.

While Carter was not a victim of domestic violence, her family believes that she would approve. “It’s not a perfect match,” Carter says, “but we really like the program.”

For now, the family will face its first holiday season without Beverly Carter – a process they know will be difficult. “The shock is wearing off,” says Carl Carter, “and we’re realizing that she’s gone.”