FLORENCE, Ky. - Some of the nation's top retired detectives will help in the search for the killer of a Florence couple, officials announced Thursday, the same day the $100,000 reward will expire.
Ninety days ago, the children of Bill and Peggy Stephenson upped the reward money they were offering for information leading to the person who killed their parents.
Investigators say the reward money has brought about more leads, but no suspects.
Boone County Sheriff's Detectives say they can prove who is responsible for Bill and Peggy Stephenson's murders because they have the killer's DNA. But, so far, they don't have a match.
Investigators have questioned more than 250 people across 14 states, but nobody has been charged.
The Stephensons' nephew, Robert Charles Stephenson, was previously considered a person of interest in the case. He's charged with murder in an unrelated case involving the death of Leigh Jennings in Indiana. Police say they tested his DNA and he was not a match.
The couple, both 74, were killed inside their Florence home on May 29, 2011. Investigators say the murderer spent a significant amount of time inside their home after the killings, arranging the crime scene in a "unique way."
The Boone County Sheriff's Office is expected to release additional details about the detectives' contributions sometime Thursday. They have dedicated a phone line and a page on their website for tips in the case. You're asked to call 859-334-8496 or visit www.boonecountyky.org/so if you have any information that could lead detectives to the murderer responsible for the deaths of Bill and Peggy Stephenson.
Copyright 2012 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.