"It's been checked for fingerprints, DNA," he said. "And obviously, we still keep it packaged after that initial processing just in case there's some new technology that comes about that we don't know about today."
While investigators hope for a break in technology, they also hope there may be a crack in the offender's conscience.
"We've got to come up with something that's going to ... allow the person who did this to ... feel good about coming forward," said Gissel. "Because it's not fair for this family to go like this. It won't be complete until, you know, this person comes forward and says, you know, 'I'm the one responsible. This is what happened.'"
"I'm confident that we will solve this case," Kaufman said. "Maybe not today, maybe not in a year, but we will solve this case."
Gissel, who has been working on Mikelle's case since the beginning and is retiring this year, said that even when he turns in his badge, he will keep searching.
"I will tell you this: I will always be thinking about it. I will always be thinking about something that can be done."
If you have information that might help solve the mystery of what happened to Mikelle Biggs, please contact the Arizona Police Department on their website, http://mesaaz.gov/police/, or by phone (480) 644-2211.