The untested kit was found four years ago during a raid on the Harvey Police Department.
Officer Buchanan, 45, has a duty-related injury, so he has not been to work for 10 months. The sheriff's office says he's on medical disability right now.
In 1997, the girl told her mother about the rape and they went to police and had a rape kit completed at the hospital. But Harvey police never sent the rape kit to be tested. Prosecutors say the attacks happened at Buchanan's Harvey home over a course of 7 months.
The victim, who is related to Buchanan, is now 24 years old and lives out-of-state.
"When we came knocking on her door, she hadn't heard about this case since 1997 when she reported it happened to her, and the defendant was taken into custody, but he was released. Fourteen years later, we now came knocking on her door telling her we were there to hear her story. We were there to help her," said Jennifer Gonzalez, Cook County S.A.'s Office, Chief of Sex Crimes Division.
This case came to light in 2007, when authorities raided the Harvey Police Department and discovered about 200 rape kits that had never been tested. Since the raid, prosecutors have charged 14 defendants in 20 separate cases.
"We have been very methodically been going through each and every one of these cases, conducting full investigations on every single one of them and bringing charges when we can," Gonzalez said.
Harvey Police say they are fully cooperating and working closely with the State's Attorney's office on all the cases. On Thursday, the police department released a statement, writing Buchanan's case predates the current administration, and "...it is unfortunate the victim did not receive justice at that time; however, the Department is grateful that the collaborative efforts between both agencies have resulted in justice for this victim and her family."
"How did Harvey allow this to be set aside for all these years?" said Mary Handy, Buchanan's neighbor.
"He wasn't a problem guy - him or his wife, or his kids. You would have never thought that something was going on in the house like that," Denise Green, Buchanan's neighbor, said.
Buchanan is currently being held at the Cook County Jail on a $200,000 bond.
Buchanan recently gave a DNA sample at the Harvey Police Department. Just this year, prosecutors recently learned that Buchanan's DNA matched the rape kit. Buchanan was arrested at the Markham courthouse.
If convicted, Buchanan could spend between 6 and 30 years in prison. He'll be back in court next month.