On this day in 2011, Jim Pitzen dropped off his then 6-year-old son Timmothy at Greenman Elementary School in Aurora.
Surveillance video captured Timmothy's mother, 43-year-old Amy Fry Pitzen, picking him up. She told the school there was a family emergency.
"I know he's out there and somewhere else, it's just a matter of time before I find him or he finds me," Jim Pitzen said.
WATCH | Age-progression photo of Timmothy Pitzen released
Police said Pitzen took her son to Brookfield Zoo and to Key Lime Cove in Gurnee. On May 12, they checked into the Kalahari Resort in the Wisconsin Dells.
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Timmothy and his mom were last seen together on the morning of May 13, checking out of the resort.
Police said Pitzen then checked herself into a motel in Rockford, Illinois, that night. She appeared to be alone.
She was found on May 14 after she died by suicide.
Police said Pitzen left a suicide note that said, "Tim is somewhere safe with people who love him and will care for him. You will never find him."
So far no one has, including Aurora police who say they continue to investigate the case but have no strong leads.
"It haunts everyone who works on this case. It's the unknown. We don't know, is Timmothy alive somewhere?" said Lt. Greg Spayth, Aurora Police Dept.
Two years ago, relatives got a glimmer of hope when a man in Cincinnati came forward claiming to be Pitzen, saying he escaped from his captors. It turned out to be a cruel hoax. The imposter was charged and convicted, and relatives were left back at square one.
Ten years from the last time he saw Timmothy, his father remains determined to continue the search to find his son.
"Timothy is out there. Don't be afraid to come out and say, 'I think I've seen him here, I think I've seen him there,'" Jim Pitzen said. "Or he might be sitting next to you right now and you don't even know it."
Aurora police say they are keeping an open mind in their investigation. They say it's been quite a while since they had what they consider a substantial lead, but they are hoping the release of the age progression photo will spur more calls.
Anyone who may have information is asked to call The National Center for Missing & Exploited Children at 1-800-THE-LOST (1-800-843-5678) or the Aurora Police Department's Timmothy Pitzen Tip Line at (630) 256-5516.