Peterson appeared on NBC's "Today Show" with his lawyer, who dismissed pathologist Dr. Michael Baden as having a "pre-determined" opinion that Savio died as the result of a homicide in 2004 rather than a bathroom accident.
"The results of Dr. Baden's autopsy on Ms. Savio do not surprise us ... because Dr. Baden had indicated the conclusion before he conducted his autopsy that he believed Kathleen's death was not an accident," said attorney Joel Brodsky, the Chicago Tribune reported.
The Chicago Sun-Times said Monday Savio's family was standing by Baden's conclusions.
Brodsky, who did most of the talking on the "Today" segment, also questioned whether or not Baden's long-running role as a crime commentator on Fox News might have swayed his conclusions.
Peterson's first wife, Carol Brown, appeared on "Good Morning, America" Monday and said though Peterson could be overbearing at times, she did not think he was capable of murder. Their marriage broke up, she said, because of his infidelity.
The disappearance of Peterson's current wife, Stacy, has become a major running story on cable channels and other media outlets. Peterson has denied any wrongdoing and again Monday appealed to his missing wife to come home.