05/11/2012 04:50 pm ET Updated May 11, 2012

Timmothy Pitzen Missing: One Year After Disappearance, Police Still Searching For Clues

One year after six-year-old Timmothy Pitzen vanished with his mother, who was later found dead in an apparent suicide, police are renewing their appeal to the public for help finding the missing child.

On May 11, 2011, Amy Fry-Pitzen, Timmothy's mother, checked her son out of the Greenman Elementary School in suburban Aurora, Illinois, 40 miles west of Chicago. She then set out on a three-day, 500-mile road trip with her son in tow, before slitting her wrists in a hotel room at the Rockford Inn.

A note found at the scene of her suicide read that Timmothy was safe "with people who love him and will take care of him," but that he would never be found.

Soon afterwards, police found the 2004 Ford Expedition Fry-Pitzen was driving. It contained a sizable amount of blood in the back seat, which lab reports determined is Timmothy's.

But family members say the blood may have come from a bloody nose, and authorities couldn't say how long the blood had been there.

Police released additional surveillance video Friday of Amy and Timmothy at two different resorts in Gurnee and Wisconsin Dells in the two days after they disappeared, according to NBC. Police say they hope the new footage will help renew public interest in the case and generate more tips.

Fry-Pitzen's family says they remain concerned about the boy's safety. Amy's mother, Alana Anderson, told the Chicago Tribune she was angry when she visited her daughter's grave on what would have been her birthday last week.

"I yelled at her," Anderson told the Tribune. "I told her this was a very stupid thing to do, that she had other options and that she hurt lots of people but that she probably hurt her son the most."

Police are asking land owners and outdoor enthusiasts in surrounding counties to look for some of Amy and Timmothy's possessions that have not yet been located, including Amy's cellphone and I-PAASS, Timmothy's Spider-Man backpack, other toys and a tube of kids Crest toothpaste, the Daily Herald reports.

(See police photos of Timmothy's missing items below.)

Aurora police continue to investigate occasional reports of Timmothy sightings from across the nation, and the National Center for Missing and Exploited Children still is a partner in the investigation, according to WIFR. Anyone who may have information about Timmothy is asked to call Aurora police at (630) 256-5500 or Aurora Area Crime Stoppers at (630) 892-1000.

Timmothy would be 7 years old now. When he went missing, he was 4 feet 2 inches tall and 70 pounds with brown hair and eyes.