48 Hours: Five years pursuing the Harkness-Sisco murders

Mike Sisco and Karen Harkness
Mike Sisco and Karen Harkness

(CBS) In the summer of 2011, it was 112 degrees in Duncan, Okla., while I watched half a dozen law enforcement officials dressed in bulletproof vests point heavy firearms at one Dana Chandler, age 51. She was accused of killing Mike Sisco and Karen Harkness in Topeka, Kansas, on July 7, 2002.

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Video of Dana Chandler's arrest

In broad daylight, they pulled her car over into an Arby's parking lot and arrested her as bystanders, who had been eating lunch, took pictures and videos with their phones. It was a moment that was a long time in the making and took the joint cooperation of four agencies: Shawnee County District Attorney's Office, Kansas Bureau of Investigations, Topeka Police Department and the Oklahoma State Bureau of Investigations.

We at "48 Hours" first became aware of the crime back in 2008, when a report written a year earlier by Vernon Geberth, a retired lieutenant Commander of the New York City Police Department with the Bronx Homicide Task Force and a well respected homicide and forensic consultant, came to our attention. Despite outlining the case and identifying Dana Chandler as "the one, and only person who had the motive, means and opportunity to have committed these murders," no charges were ever filed.

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Even more compelling was that Dana Chandler's own children, Hailey and Dustin -- who were 17 and 15 at the time of the murders -- were vehement that their mother killed their father and his fiancée. They were willing to come forward and say that on camera, even though she had never been publicly named as a suspect. It was a big risk, since they were afraid of their mother and she was known to show up on their door steps without warning.

Despite detectives' original reservations that a woman who lived eight hours away in Denver could be responsible for these homicides, the victims' families had long suspected Mike's ex-wife, Dana Chandler. It became more feasible when they discovered that she had a 27-hour window where no one heard from her, and that she had bought two 5-gallon gas tanks the day before the murders. While we were researching, we made sure to check into alternative theories to ensure that no stone was left unturned.

We re-interviewed all the family members and spoke to people who knew Mike and Dana as a couple, as well as separately. We went to the crime scene, went through the Siscos large divorce file, and read various psychological reports that had been done. We headed out to Colorado to check Dana's alibi. In addition, we made several attempts to try and speak with Dana herself, but she would not agree to talk to us on or off camera.

In 2009, a new district attorney, Chad Taylor, took office in Shawnee County. I waited until he had been in office about two weeks before I gave him a call. He told me later that his initial reaction was, "what have I done to have '48 Hours' calling me." We arranged a face-to-face meeting so I could talk about our interest and work on the case. He made it possible for us to meet and interview with the lead detective, Richard Volle. Little did I know that even before Taylor had won the election, Det. Volle had met Taylor while he was campaigning for office and Volle mentioned the Chandler case, and that he thought it was a solid case if someone would be willing to work it. Taylor had inherited almost 4,000 cases on which his predecessor, Bob Hecht, had declined to file charges. But among all those cases, Taylor agreed that the Chandler case deserved a second look and made it a priority again.

"48 Hours"' original report aired in October 2009. After that, Taylor, Chief Deputy District Attorney Jacqie Spradling and their team worked the case for two years. They faced an uphill battle as they had no forensic evidence that put Dana Chandler at the crime scene -- or even in the state of Kansas. They sent previously untested samples for evaluation, tracked down witnesses and, in general, worked to plug holes in the case that was almost a decade old.

Finally in March 2012, the case went in front of a jury. There was about two weeks of testimony including the defendant's own children which was very emotional and hard to watch. There was a lot of tension in the court room as a lot of testimony had been ruled inadmissible. This was a purely circumstantial case and, these days, juries like to see DNA, fingerprints -- something concrete that they can point to before convicting someone.

The families of the victims were nervous and weren't sure, despite a pile of circumstantial evidence, how this was going to end. They didn't have to wait long -- just 83 minutes before we heard there was a verdict. Later, when we interviewed the jury, they told us they actually had a decision within 15 minutes of deliberating and felt strongly about delivering the verdict right away so the families didn't have to wait one more day.

The jury handed the form to the court clerk and she read it: Guilty on both counts of murder. The defendant, Dana Chandler, hardly had a reaction. But a flood of emotion came over the victims' families - relief mostly, but certainly not happiness - especially for the children who had now lost two parents from the events that took place that day.

Watching the moment unfold, it was hard not to get swept up in the emotion. It had been a long wait for justice and a lot of work for all involved: 10 years for the two families that never stopped pushing to get justice for their loved ones, for the lead detective, now sergeant, who had never stopped thinking about the victims, and the prosecution team who had the courage to bring a case to trial that certainly was no slam dunk.

There were congratulations all around and many people came up to me and thanked me for the role that "48 Hours" played in getting this case the attention it deserved. Cathy Boots, Mike's sister, told me that our coverage of the case was "life saving" for the family. That she thought "'48 Hours' pushed a lot of buttons to get it solved." Her husband, Mark Boots, agreed and added that "Without the '48 Hours' team, we would not be here today without the support and the help."

The final chapter came on Aug, 20, 2012, ironically what would have been the 30th anniversary of Dana and Mike's wedding; Dana Chandler was sentenced to two life sentences. She must serve a minimum of 50 years for murdering Mike Sisco as well as a minimum of 50 years for murdering Karen Harkness. She will be 151 years old before being able to request parole.

After five years of working with the professionals on this case and getting to know the families, I must admit I felt a deep satisfaction that the case was finally solved. We at "48 Hours" dedicate ourselves to these cases -- there are many long hours, lots of travel and reams of tape shot. The families open up themselves and their homes to us during very difficult times in their lives and we don't take that lightly.

It was rewarding to finally see all their struggles come to a close. Harold Worswick, Karen's father, had aged a great deal since I first met him. He carried the burden of finding Mike and Karen after they had been shot to death and the unsolved murders weighed heavily on him. He believes that the event launched his beloved wife, Betty, into dementia. Sadly, she died just before the trial started. Harold now feels that he fulfilled the promise he made to get justice for his daughter and he has been able to find some peace.

Karen's daughter, Erin, was devastated by the loss of her best friend. She now has two lovely children and the fact that she can't share that joy with her mother is painful beyond words. Every day has been torture for Hailey, Mike's daughter, because she has had to live with the fact that she and her dad were fighting when he died and that she never had the opportunity to apologize to him and re-establish that important relationship. It is a regret that she has had to live with and, I believe, the impetus that drove her to such extraordinary measures to make sure he got justice -- even if it meant pursuing her own mother.

Dustin, Mike's son, says his life's trajectory completely diverged that fateful day and he struggles to find his new path. And we at "48 Hours" suffered a loss as well. I started covering this story with correspondent Harold Dow. He believed strongly in this case and was passionate about seeing it solved. Sadly, he never lived to see it. He died August 2010. We dedicate this show to him.