Mellon was 13 years old when she disappeared from her home on January 31,1996.
She was last seen wearing yellow sweatpants, a pink top, red house-slippers and was wrapped in a blue blanket.
RELATED: Rachel Mellon's disappearance from Bolingbrook home remains unsolved 25 years later
The age progression image created by the National Center for Missing & Exploited Children shows what she might look like now at age 38.
Mellon's father, Jeff Skemp, recently spoke with the I-Team about her disappearance. He said he would like to see justice for his daughter in the form of an arrest and conviction for Rachel's abductor and likely killer. He said his daughter lives only in his heart now.
"I know she's in a better place," said Skemp. "And she's not suffering."
The video in this story is from a previous report