He said only that authorities hope it will help with the identification of one of the sets of remains found Monday.
Almost 100 investigators were expected to search the area where the remains were discovered Thursday, officials said. The second set of remains has not been identified. Runions was last seen in the company of Kylr Yust, who has been charged with burning her vehicle, which was found two days after her disappearance in a wooded area near where she was last seen.
On Tuesday morning, a second human skull was located in the same search area deputies say.
Video surveillance from Belton High School on May 4, 2007, is the last video of Kopetsky alive. Court records indicated Kopetsky filed for a protection order against Yust in April 2007. The unnamed victim told police that Yust told her, "I've killed people before, even ex-girlfriends out of sheer jealousy".
The families of both young women were asked to speak to investigators on Tuesday.
Yust's attorney, Molly Hastings, said earlier to ABC News, "Kyler has not been charged with anything, with anything outside of knowingly burning a vehicle, again, a charge he plead not guilty to, and that we intend to fight".
MTV Movie & TV Awards eliminate gender divisions
The 2017 MTV Movie & TV Awards, hosted by actor Adam Devine, will take place at the Shrine Auditorium in Los Angeles on 7 May (17).
Yust had been seen with Kopetsky several times in the months leading up to her disappearance.
Relatives who reported Dante Jamal Jefferson missing in January told Merriam police they had not seen him since December 5.
While Yust, 28, was charged with the burning of Runions' auto, there have not been any charges laid against him in relation to Runions' disappearance. The second set of remains has not been identified. Yust also dated Kopetsky. But we need a resolution to this and we need to find out what happened to our girls.
It was not immediately clear whether Yust, 28, will face additional charges now that the remains have been found.
Kansas City policearrested 28-year-old Kylr Yust on a warrant for burning the vehicle on September 11, a day after the burned vehicle was found.
Rhonda Beckford, Kara's mom, was with the Runions family when word broke of the identification.