Thirteen-year-old Ima Jean Sanders is now believed to be among his victims.
Authorities recently matched genetic material taken from DNA samples submitted by Sanders’ mother and a sister to DNA submitted by the GBI in 2008 from skeletal remains found in a wooded area in 1976. The GBI had kept the bones as evidence.
The match was made through the FBI’s Combined DNA Index System, a national database containing known DNA of convicted criminals and missing persons and questioned DNA from unidentified bodies and crime scenes. The database, commonly referred to as CODIS, became fully operational in 1998.
“CODIS is what solved this case,” Warner Robins police Capt. Chris Rooks, one of the investigators on the case, told The Telegraph of Macon.
With CODIS matching the remains to Sanders, authorities next linked the then-U.S. Attorney’s summary of the serial killer’s audiotaped descriptions of the Georgia crimes that were based on what a 1975 federal grand jury likely heard.
Copies of the tapes and transcripts were ruined when the federal courthouse in Macon later flooded.
Authorities believe Knowles, then 28, of Orlando, Fla., picked up Sanders as she was hitchhiking, and took her to a wooded area where he raped and then strangled her.
Gary Rothwell, special agent in charge of the GBI office in Perry, who also investigated the case, said when the GBI first began working with DNA evidence, agents couldn’t even consider cases older than Jan. 1, 1989.
Starting the new program, authorities knew it would be deluged with information, said Rothwell, who joined the GBI in 1981. As a result, the cut-off date was set.
It would be into the 1990s when DNA forensics evolved to include the ability to glean information from bones and teeth, Rothwell said.
Within CODIS, the National Missing Persons DNA Database Program for the identification of missing and unidentified people was developed in 2000.