KANSAS CITY, Mo. -- Remains found in rural Cass County in April were identified as Kara Kopetsky, Wednesday. A woman who has inside knowledge of the investigation of the prime suspect in Kopetsky's disappearance spoke exclusively to FOX 4 on Thursday.
"He will be charged with both murders because he killed both girls," said private investigator Marlene Rockwell.
Yust is in the Jackson County jail, awaiting trial for burning up Jessica Runions' car. Twenty-one-year-old Runions disappeared September 8 after leaving a party with Yust. Three days later, her car was found in a park after being set on fire.
While Yust is the main suspect, he has not been charged in the disappearance of either woman.
Rockwell volunteered her services to Kopetsky's family several years after she vanished in 2007.
"I couldn't believe that that the case had gone on so long," Rockwell said. "I wanted to get involved because I didn't think the case was rocket science."
Rockwell says there is no other suspect, no other possibility and law enforcement had enough evidence to charge Yust long ago. Kopetsky had a restraining order against her ex-boyfriend, Yust. Rockwell said he failed a polygraph test and Rockwell interviewed several of Yust's friends who told her Yust confessed to killing Kopetsky. As an investigative insider, Rockwell says there is much more evidence which she could not talk about.
Yust is the last person known to be with Kopetsky after she was last seen leaving Belton High School.
"I believe that she was arguing with him at school and as she walked out the door, I believe that he grabbed her by the hair, pulled her in his vehicle," Rockwell said. "I believe that by noon, he had strangled her"
When Kopetsky's parents went to the former Cass County Prosecutor, Rockwell said they were turned away.
"And she refused and said she would never try a circumstantial case. Which, I don't even get that," said Rockwell. "All cases are circumstantial. Circumstance means truth."
Rockwell hopes for long overdue justice. Although she says even with Kopetsky's remains, if Yust is charged with Kopetsky's murder, the case will be built with evidence law enforcement has had for nearly a decade.
"You are not going to be able to tell the cause of death, there is no DNA. We have proof that she is deceased. That is what we gained from that," said Rockwell.
Rockwell said her biggest regret is that in her opinion, if law enforcement had done its job better in the Kopetsky case, Runions would still be alive.