The Indiana Department of Correction placed Anthony Ray Stockelman, 39, in protective custody away from the general inmate population last weekend after authorities discovered the tattoo, said Rich Larsen, a spokesman for the Wabash Valley Correctional Facility.
Stockelman was sentenced to life in prison after pleading guilty to abducting, molesting and killing Katlyn "Katie" Collman. She was missing for five days before her body was found Jan. 30, 2005, in a creek about 15 miles from her home in the southern Indiana town of Crothersville.
Larsen refused to comment on what Stockelman has said about it or what else investigators have learned. He said he did not know how a picture of the crude tattoo was taken and distributed outside the prison, including on the Internet.
Collman's father, John Neace, said he heard about the tattoo from friends and believes it was the work of inmates.
"If I had to guess, I'd say it's a statement from the inmates," he said Wednesday. Neace said has no idea whether his late daughter's distant cousin, who is also serving time at Wabash, played any role.
Stockelman's tattoo, which covers nearly his entire forehead, has "KATIE'S" in large letters and "REVENGE" below in smaller letters.
The search for Katie, a bright child who enjoyed basketball and the Disney Channel, had consumed Crothersville. Police initially believed she was abducted and slain so she would not reveal methamphetamine activity in her neighborhood.
Investigators had interviewed Stockelman early on because he matched the description of a man seen with the girl. Then another man told police that he was involved in the murder. That confession was eventually shown to be false as evidence pointed investigators back to Stockelman and DNA from the crime scene was found to match his.
A message seeking additional comment left Thursday for an Indiana Department of Correction spokesman was not immediately returned.