Sassy - Can you provide a link to where he "admitted to killing someone in Ocilla"? That's the first I've heard of that and it would be an interesting read.
According to the article you posted, it says:
BBM
Tara went missing from her home, not a "remote" location. There is proof she was home after the pageant and BBQ (other than her car being home).
Investigators say he confessed to killing one person on the East Coast, but nothing about Ocilla, GA, and that was in 2009. Tara disappeared in 2005.
As well, according to the FBI Press Release (attached), Keyes was believed to be on the West Coast (WA state area) in 2005 and 2006.
From what I've read about Keyes, I don't believe there is any connection between him and Tara.