Janesville50°

Triple homicide case relies on DNA evidence

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Ted Sullivan
December 23, 2009
— When the Janesville triple homicide trial begins in January, DNA will play a key role.

Prosecutors claim the victims’ DNA was linked to bloodstains on the jeans and shirt that James Koepp wore on the night of the homicides.


Defense attorneys claim DNA from an unknown assailant was found on a ligature and knives at the murder scene.


Koepp, 50, faces three charges of first-degree intentional homicide in the January 2007 slayings of Danyetta Lentz and her teenage children, Nicole and Scott.


A pathologist said strangulation by ligature and stab wounds contributed to their deaths.


Jurors will have to decide whether DNA shows that Koepp or someone else is the killer.


Attorneys on both sides appeared in Rock County Court on Tuesday to argue whether an unknown assailant defense would be allowed at trial. Koepp didn’t attend the hearing.


District Attorney David O’Leary filed a motion asking the judge to keep the unknown assailant defense out.


Koepp’s attorney, assistant public defender Walter Isaacson, said Koepp has a right to undermine the state’s DNA evidence.


He said the state crime lab found DNA from an unknown male on a ligature, knife handles and other items at the crime scene.


Judge Alan Bates sided with the defense attorney, saying the unknown assailant defense could be used at trial.


Meanwhile, attorneys argued over the testimony of a DNA expert that the defense wants to call at trial.


State statutes require attorneys on both sides to exchange evidence or testimony they intend to present at trial. Attorneys then have an opportunity to review each other’s cases to prepare.


O’Leary said a defense expert’s report offers no opinion challenging the state’s DNA evidence. He said he hasn’t been told what the defense expert will say at trial.


“It’s not fair to the state,” O’Leary said. “It’s trial by ambush.”


Isaacson denied the prosecutor’s accusations, saying the expert will testify about DNA transfer and other elements of her expertise.


The judge decided the expert could only testify about information in her report. He ruled the expert can’t provide opinions not shared with prosecutors.


If convicted, Koepp faces three life sentences.


A hearing is scheduled for Tuesday, Jan. 19.


Koepp’s two-week trial is scheduled to begin Jan. 25.



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