CHICAGO (CBS) — Timmothy Pitzen has been missing for more than eight years, but his father is still confident the boy who would now be 14 will be found someday.

“We’re going to eventually find Timmothy. I know that in my heart. It’s not an if – it’s a when type of thing at this point,” Jim Pitzen said in an exclusive interview with Dr. Phil.

Timmothy has been missing since 2011, when his mother was found dead in Rockford, after pulling the 6-year-old out of school and taking him on a trip to Wisconsin. He would be 14 years old today.

Just last month, a 23-year-old Ohio man was arrested after he allegedly impersonated Timmothy. Brian Michael Rini is accused of telling police he was the missing boy, and had just escaped from two kidnappers who had been holding him for seven years, after he was seen roaming alone in Newport, Kentucky.

After Rini was taken to a hospital in Cincinnati, DNA tests confirmed his real identity.

“When this had happened, I was at work. The detective on Timmothy’s case called me and said that they had a lead in Kentucky. I got another phone call later that night, and he goes ‘The person does not carry himself as a 14-year-old.’ Then they took DNA, and it came back that it wasn’t Timmothy,” Jim Pitzen said.

Rini was later indicted on two counts of making false statements to the FBI and one count of aggravated identity theft.

Aurora police have said, even though Timmothy hasn’t been found, they believe renewed attention in the case might help bring new leads.

Timmothy was six years old when he went missing in May 2011. Timmothy’s mother picked him up from school in Aurora, and then took him to Brookfield Zoo and the Key Lime Cove Resort in Gurnee. They checked into the Kalahari Resort in Wisconsin Dells the next day. The last time Timmothy was seen alive was one day later, when they checked out of the Kalahari Resort.

Amy Fry-Pitzen was found dead two days later at a hotel in Rockford, after she slit her wrists. She left a suicide note indicating Timmothy was fine, and she had left him in the care of unnamed people, but that no one would find him.

Timmothy’s aunt, Kara Jacobs, told Dr. Phil she still believes he’s alive, but she doesn’t how Timmothy’s mother found someone to take him in for all this time.

“That’s the million dollar question that I don’t know that we’ll have the answer to until we find him, and if he remembers,” she said.

It’s unclear why Rini allegedly impersonated Timmothy, but authorities have said he made similar false claims at least twice before, portraying himself as a juvenile sex trafficking victim.