FRANKLIN, Ind. (AP) – Billboards seeking leads in an unsolved murder case have popped up along a busy highway in central Indiana.

Police hope the three billboards that recently went up on Interstate 65 will prompt someone to come forward with information about the stabbing deaths of Blake and Chynna Dickus. The 10-year-old boy and his stepmother were found dead in their Franklin home in July 2006.

Officers determined Sean Dickus wasn't guilty of killing his son and wife. No other suspects have been identified through nearly 500 leads in the past nine years.

But investigators refuse to call it a cold case, and four detectives are still actively working it.

A $25,000 reward is being offered for information leading to an arrest.