(NewsNation) — Osage and Pawnee County District Attorney Mike Fisher addressed media speculation Monday regarding a potential connection between serial killer Dennis Rader and the disappearance of Cynthia Kinney, a 16-year-old cheerleader who was last seen at a laundromat in Pawhuska, Oklahoma, 46 years ago.

Fisher told the press that the information that has been shared within the past 30 days is insufficient to file charges against Rader, saying any “rumors” as to other potential evidence don’t even rise to the level of reasonable suspicion.

However, Fisher has asked the Oklahoma State Bureau of Investigation to open a formal investigation into Kinney’s disappearance.

Fisher said he has called upon the OSBI to help investigate because he wants to make sure that the information is being gathered appropriately, saying the things he has seen conducted by the Osage County Sheriff’s Office have given him “pause and concern.”

The district attorney said it wasn’t appropriate for the sheriff to conduct a dig at Rader’s previous residence before using proper investigative techniques.

However, if evidence does come to light in the Kinney case, the district attorney’s office will file charges appropriately.

Fisher asked the media to respect the Kinney family’s privacy, explaining that the recent speculation and “rumors” have brought the elderly couple tremendous stress.

Rader, also known as BTK, which stands for “bind, torture and kill,” was convicted in 2005 of killing 10 people from 1974 to 1991. However, recently, authorities believe there are at least five missing persons cases that could be connected to him.

His daughter, Kerri Rawson, believes there could be more victims.

The investigation into whether Rader was responsible for additional crimes started with the reexamination of Kinney’s disappearance.

The cases also include that of 22-year-old Shawna Beth Garber, whose body was discovered in 1990. An autopsy revealed she had been raped, strangled and restrained with bindings about two months before her body was found in McDonald County, Missouri.

Missouri detective Lorie Howard has spent hours speaking with Rader and said she’s always found him to be “very cooperative.”

As part of the investigation into Rader, authorities conducted a dig this week near his former Kansas property in Park City, finding “items of interest” including tangled pantyhose, which were shown to NewsNation by lead investigator Osage County Sheriff Eddie Virden.