DNA experts at odds as testimony wraps up

What's new: Testimony concludes after 13 days of evidence.

What's next: Closing arguments are slated to begin Wednesday.

Testimony ended Thursday in the Brown's Chicken murder trial following 13 days of gruesome evidence from the bloodiest crime in suburban Chicago history.

Closing arguments will be heard Wednesday. Jury deliberations may begin later that afternoon.

Though prosecutors used the majority of their case to replay the horrific slayings inside the Palatine restaurant on Jan. 8, 1993, they ended it with numbing scientific testimony to reinforce the probability that Juan Luna's genetic code matches DNA found on two half-eaten chicken bones at the scene.

In keeping with other prosecution witnesses, acclaimed DNA scientist Ranajit Chakraborty told the jury Thursday that the genetic profile linked to Luna could match only 1 in 2.8 trillion people.

A defense expert, however, had testified the DNA profile could appear in 1 million other people across the country.

Those divergent figures could matter to jurors when deciding whether Luna, now 33, helped kill seven people at the Palatine restaurant 14 years ago. Prosecutors allege Luna, a former Brown's employee, and his high school pal Jim Degorski fatally shot the establishment's two owners and five workers in a "quest to do something big."

The pair were not arrested until 2002, when a witness finally came forward saying they told her of their role in the crime soon after it stunned the region.

The men, who are being tried separately, have pleaded not guilty. If convicted, they could face the death penalty.

Prosecutors say they can link Luna to the crime scene through a partial palm print on a discarded napkin and DNA on the chicken bones. Both pieces of evidence were found in a near-empty trash can that authorities say contained remnants from the killer's meal.

At least two people's DNA was found on the food, but authorities have been able to link only Luna to it. They have never been able to determine the second source.

Both sides stipulated Thursday that Degorski, 34, does not match the second profile.

Defense experts even concede Luna is not excluded from chicken bone DNA. Chakraborty testified that fact means Luna is at least 234 million times more likely to be one of the contributors than any random person.

Put another way, Chakraborty said a random person picked off the street would have a 99.999 percent chance of being excluded from the DNA sample. Luna had those same odds, he added, but wasn't excluded.

His numbers contradict an earlier defense witness who told the jury more than 1 million people in the United States could have the same DNA profile prosecutors are using.

The minuscule amount of DNA found on the chicken only allowed for the testing of nine genetic markers. Current forensic standards suggest at least 13 markers be used in comparisons, a defense expert testified.

The defense also suggested the DNA evidence had been tainted and mishandled. Witnesses have testified to handling the bones without gloves, ripping meat of the bones and thawing and refreezing the pieces several times.

The state police crime lab handling the testing lost the DNA swabs taken from the chicken pieces and the hard data collected from the computer.

On their final day of testimony, prosecutors also called assistant Cook County medical examiner Mitra Kalelkar to refute testimony from a defense witness that said restaurant owner Lynn Ehlenfeldt's throat was slashed after she was shot. Luna said in his videotaped confession that he slashed her throat before a bullet was fired into the back of her head.

All seven victims -- Lynn Ehlenfeldt, Richard Ehlenfeldt, Rico Solis, Michael Castro, Marcus Nellsen, Thomas Mennes and Guadalupe Maldonado -- died from gunshot wounds.

Though the defense expert insisted Ehlenfeldt's blood flow patterns proved she had been knifed after her death, hemorrhaging in the tissues around the wound showed she was alive when it happened, Kalelkar said.

If Ehlenfeldt's throat was slit after her death, it would cast doubts on the veracity of the 43-minute videotaped statement. It also would bolster the confession of a former suspect who told police his friend stabbed Ehlenfeldt after she was already dead.

The defense challenged Kalelkar's scenario, questioning why someone would slash Ehlenfeldt's throat in one place and then put her in the restaurant's freezer with four other people to kill her. Kalelkar responded that if the murder already had herded a group into the refrigeration unit, they would not hesitate to put others in there.

"They probably wanted a more convenient place to shoot her," Kalelkar said. "I don't know, I haven't shot anyone."