ORANGE PARK, Fla. -- It's been three weeks since 7-year-old Somer Thompson vanished while walking home from school.

Her murder case is now getting national exposure, and investigators have released sketches of items they said were with her when she vanished.

Investigators said Somer used her tote bag to carry books. The bag is pink with black straps and has a white skull and crossbones design.

The round lunch box with a zipper was also pink with a pig design.

Diena Thompson, Somer's mom, is renewing her vows to get justice for her daughter's killer, determined to keep her daughter's story in the national spotlight.

She taped an interview for Dr. Phil on Monday and appeared on ABC's "Good Morning America."

She talked about how the killer could be someone living in her neighborhood, even someone Somer knew.

"I don't know what to think," Diena Thompson said. "I thought, 'Please don't let it be one of these people that's coming around and hugged me and said how sorry they were.'"

When asked what if it is someone she knew, Diena Thompson said, "God have mercy on their soul, and they better be lucky that the Clay County Sheriff's Office is going to get to them before I do."

The search for Somer's killer was also featured on "America's Most Wanted" on Saturday.

"We're going to get him," Diena Thompson said. "We're looking for you. You won't get away. This is not OK, and my voice will be heard for Somer."

The sheriff's office said it has now received more than 3,300 tips in the case.