Melissa Myhand testified Friday that no usable DNA matched Dirksmeyer's boyfriend, Kevin Jones, as well as the man currently on trial in her death, Gary Dunn.
State Medical Examiner Dr. Charles Kokes is expected to testify later Friday.
The 19-year-old Dirksmeyer was found brutally beaten in her Russellville apartment on Dec. 15, 2005. Her boyfriend, Jones, was acquitted of the crime three years ago.
Police arrested Dunn in 2008 after investigators say DNA evidence found on a condom wrapper linked him to the crime.
The trial is expected to enter its third week on Monday.
Thursday, Kevin Jones' mother Janice took the stand, as well as Nona's mother and stepfather Carol and Duane Dipert and a scientist from the Arkansas State Crime Lab.
They all testified about what they remember from the day Nona died in 2005, and the scientist testified about collecting evidence from Nona's cell phone.
Kevin Jones took the stand Wednesday, describing how he found Nona in her apartment, and apologized for contaminating the crime scene by straddling her and performing mouth-to-mouth resuscitation
In 2008, Today's THV talked with Kevin Jones and his mother Janice. Check out the story as well as the extended interviews with both.
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