But it was in a manner similar to the conclusion of the Golden State Killer case that Fort Wayne and Indiana State police zeroed in on Miller.
Tinsley's body was found in a ditch, about 20 miles from her Fort Wayne neighborhood, three days after she disappeared in April 1988.
Miller, 59, was arrested on preliminary murder, child molesting and criminal confinement charges in Tinsley's death.
Miller will have an initial hearing on the charges Monday morning in the Allen Superior Court in the Bud Meeks Justice Center, 715 S. Calhoun St., the announcement said.
Tinsley was abducted as she walked to a friend's home to pick up an umbrella, the station reports. Early the morning of April 2, 1988, he put her body in his auto and drove to DeKalb County Road 68 near Spencerville, where he dumped the body in a ditch along the road.
On July 6, police searched Miller's trash in an attempt to find items bearing the suspect's DNA, according to court documents.
The mysterious killer's taunting messages admitting to the crime, scrawled on a barn door and on paper notes threatening to kill again, only added to the desire to solve the cold case.
Fourteen years after that, four taunting notes were found at various Fort Wayne residences, including several on bicycles that young girls left in their yards, the Federal Bureau of Investigation said.
Miller told police he choked her for about 10 minutes until she died, so she would not report him to the police, the affidavit said.
Suspected serial killer Joseph James DeAngelo, known as the Golen Stater Killer, was arrested after police used the same technique to track him down in April. The defendant replied "yes" and said nothing else, CBS News affiliate WANE reported.
As the case stalled, and hundreds of suspects were targeted and cleared, the girls assailant would continue to haunt the Fort Wayne area.
With this new information, detectives began monitoring John Miller, who was the only named brother from the affidavit. Police said April had been raped.
On July 9, police received news from the Indiana State Police lab that the DNA profile extracted from the condoms in Miller's trash matched the DNA profiles of the condoms found in 2004 and the DNA found in Tinsley's underwear.
"You got an 8-year-old girl that was sexually assaulted and strangled", Fort Wayne Police Detective Cary Young told Crime Watch Daily. He then found her shoe in the vehicle and tossed it out in a ditch, as well, the affidavit said.
"We thought aint nobody really going to show up", Janet Tinsley told the Fort Wayne Journal Gazette. DNA evidence found in the girls underwear also did not initially point to a perpetrator.
"Hi Honey I Been watching you I am the same person that kinapped an Rape an kill Aproil Tinsely", the messages said.
Sunday morning, Martin and a state police detective approached Miller outside his mobile home.
Miller then admitted to abducting April from Hoagland Street in Fort Wayne on April 1, 1988, taking her to his trailer, raping her and killing her, court documents said.
Miller said he then drove Tinsley's body to C.R. 68 in Spencerville and dumped her.
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