DNA links Sanchez to victim
Expert testifies that samples found on Juli Busken's leotard are 'consistent' with Anthony Sanchez's

by Meredith Simons & Grant Slater

February 14, 2006

One person out of 94 trillion carries the same DNA in his or her cells as the person who killed Jewell “Juli" Busken — the same DNA that breathed new life into a cold case.

Life came in 2004 when the Oklahoma State Bureau of Investigation notified Oklahoma City police of a match in the Combined DNA Index System. This match linked Anthony Castillo Sanchez to the 1996 homicide.

Melissa Keith, DNA analyst for the Oklahoma City Police Department, was the only witness called to testify in the Busken murder trial Tuesday. After her testimony, the state rested its case.

“DNA testing has a tremendous discriminating power,” Keith said.

Keith said “assuming one donor," one out of 94 trillion individuals of southwestern Hispanic descent would match the unknown DNA profile found on Busken's clothing. This chances only decrease when compared against white and black populations.

The population statistics come from a database and program provided by the FBI.

At the behest of Assistant District Attorney Rick Sitzman, Keith meticulously recounted for the court record and jurors the matching allele combinations at each of 15 distinct loci and one sex chromosome between the unknown DNA profile from Busken’s leotard and Sanchez's known profile from a buckle swab of his cheek.

After each locus, she repeated: “Again consistent with Mr. Sanchez's known sample.”

A locus is the position of a gene on a chromosome. The loci of a particular genome in sequence are used to create a genetic map. An allele is an alternate form of a gene at a specified locus. Different allele types make up for the differences in human genes.

“There was no elimination,” Keith said, after reading the results to the end. “They were found to be the same at all loci.”

Keith read from state's exhibit 106, which contained the allele repetitions at the 16 loci for four different samples. Two known donor profiles were taken from Busken and Sanchez. There were two unknown forensic profiles taken from Busken's clothing: an epithelial cell matched Busken's profile and a sperm cell fraction matched Sanchez's profile.

Keith said a DNA profile is created from the regions of a DNA strand, known as introns, that do not provide a blueprint for the coding of proteins because the greatest variations in allele frequency occur in these areas.

Keith said Sanchez was the 195th donor sample submitted during the nine-year Busken investigation for analysis and comparison. There were no matches until 2004, when she received the swab taken from the inside of Sanchez's mouth.

During opening statements, Defense Attorney Diane Box said jurors should question the process by which DNA evidence was stored and tested. DNA evidence is a relatively new development in criminal law, she said.

“Think about the maintenance of the machines and the correctness of their testing procedures,” Box said.

Keith said each time a sample was analyzed in the Busken investigation, it was tested alongside a positive and negative control sample to eliminate machine errors. Although DNA technology has evolved since the late '80s, the advances make analysis faster and possible with smaller samples, not more accurate.

During a recess after Keith's testimony, the defense motioned to drop two of the charges against Sanchez, citing lack of evidence. Sitzman said the evidence to prove the rape and murder, both circumstantial and evidentiary, should rule out the possibility of such a motion.

District Judge Bill Hetherington overruled the motion.

As testimony came to an end, whispers and rumors rolled through the courtroom. The defense held a 10-minute conference with Sanchez.

Assistant District Attorney Dave Batton said Sanchez was thinking about testifying.

“If he wants to testify, that’s his decision,” Batton said. “He has some time to think about it. We really can't comment on that.”