In an effort to find some answers, families with missing loved ones gave some of their DNA on Saturday.
The Knox County Sheriff's Office and Knoxville Police Department held a DNA collection day at Knoxville Center Mall. Families who have missing loved ones could come by and give a sample for free.
This DNA information will be added into the "NamUs" Database. This database keeps track of missing people and unidentified remains from across the country.
Forensic unit officer Amy Dobbs said she hopes DNA samples will help provide answers for those families.
"A lot of times they have no where to turn, and DNA is concrete," said Dobbs. "It doesn't change like weight and height and things like that."
There are more than 994 known missing people in Tennessee. In the United States there are more than 40,000 unidentified remains.