April 4 (UPI) -- Police in Kentucky said Thursday that a person who told them he was a 14-year-old boy kidnapped eight years ago was, in fact, a 23-year-old man.
Rinni told police Wednesday he fled from his kidnappers after being held hostage since his disappearance.
"DNA results have been returned indicating the person in question is not Timmothy Pitzen," the FBI field office in Louisville tweeted.
"To be clear, law enforcement has not and will not forget Timmothy, and we hope to one day reunite him with his family. Unfortunately, that day will not be today," the FBI said.
At the time of Timmothy's disappearance in May 2011, he lived in the Chicago suburb of Aurora, Ill., and was last seen at a water park in Wisconsin. Amy Fry-Pitzen, the boy's mother, was later found dead from an apparent suicide.
Investigators said Rinni gave his birthday as Oct. 4, 2004, which aligned with Timmothy's.
Timmothy's grandmother, Alana Anderson, said it was "awful" to learn that her grandson had not been found.
"We've been hopeful, alternately hopeful and frightened, and it's just been exhausting," she said during a news conference after Rinni's identification.
"I feel so sorry for the young man who's obviously had a horrible time and felt the need to say he was someone else," she added.
Kara Jacobs, Timmothy's aunt, said the missing boy's father was "devastated once again."
"It's like reliving that day all over again," she said.
Rinni, posing as Timmothy, told police his kidnappers in 2011 were two men in a sport utility vehicle that had Wisconsin license plates. They had been holding him hostage for seven years.
A witness told CBS News Rinni "looked like he had been beat up."
"He said that he was tired and he's been passed around and he's lost," another said.
Timmothy's disappearance made national headlines at the time and his old school planted a garden in his memory several years ago.
Father James Pitzen said in 2011 he last saw his son on his way to school, but his mother picked him up from class later that day for the trip to the Wisconsin water park. Before her death, officials said she left behind a note saying the boy was cared for by others.