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Castro defense claims evidence may be tainted

Posted: March 12, 2008 1:22 a.m.
Updated: May 13, 2008 5:02 a.m.
 
SAN FERNANDO - Blood stains apparently found on Esperanza Castro's jeans, shoes and hair - which the prosecutor said was her husband's blood - may have been contaminated when they were analyzed by forensics experts after the slaying of Ramon Castro, an expert witness testified Tuesday.

When defense attorney Peter Korn pressed the contamination issue, the expert admitted there definitely was some level of contamination, though questions remain about when and where it occurred.

"(The samples) may contain something other than DNA that otherwise is not there," he said. "It is possible that Esperanza Castro's DNA is in an area where the stained area is."

The testimony from Thomas Fedor, a chemist and molecular biologist with Serological Research Institute in Richmond, came during the murder trial of Esperanza Castro, who is charged with killing her husband in 2006.

Fedor had examined evidence seized by the Los Angeles County Sheriff's Department.

Castro's husband, Ramon Castro, was found dead in his pickup truck on Sierra Highway at Highway 14 in Canyon Country on March 22, 2006. But blood was found on Esperanza Castro's clothing and hair, in the driveway of the family's Canyon Country home, and in Castro's bedroom.

On Tuesday, Fedor testified that he analyzed 15 pieces of evidence seized from Esperanza Castro after her husband's slaying: Her hair sample, shoes and jeans; blood stain samples from the driveway, bathroom and bedroom; and a metal pipe. A brown substance was found on her hair sample.
During direct examination, Fedor testified that there was a positive presumptive conclusion that the substance may have been blood that belonged to someone other than Esperanza Castro, though he was not entirely conclusive.

"It is not necessarily blood, but it is an indication that it is," Fedor said about his test results from the hair sample. "Neither Esperanza Castro or Ramon Castro can be excluded from being a component of the mixture, but there can be another contributor."...to here.

He added that while there may be others who may have contributed a component to the analyzed stains, statistical analysis indicated that the DNA profile he found in his research appeared to match Ramon Castro.

"In the samples, there is DNA that resembles Ramon Castro's profile," he said. "There is a very, very slim chance of coincidence. The odds of coincidence are one in five sextillion." A sextillion has 21 zeros.

Despite the statistical evidence, Fedor added that he was unable to make a conclusion about three stains found on Esperanza Castro's jeans, which county Deputy District Attorney Paula Gonzales tried to identify as Ramon Castro's blood.

"The DNA taken from the three stains on the jeans were a mixture of more than one component," Fedor testified. "Ramon Castro's DNA was a major component of two of the stains. I am not sure if the major component for one of the stains was Ramon Castro's. There was not sufficient DNA in that stain to make a conclusion."

Fedor also testified how he analyzed the DNA results. Through a process called polymerase chain reaction, a technique used to produce millions of copies of a particular stretch of DNA, he researched various spots along the DNA strand to determine where there was a mixture of blood or other substance.

During cross-examination, Fedor said that DNA evidence on someone's clothing or body can come from anywhere.

"We expect to see DNA on people's clothing and it is possible to see foreign DNA because people wear clothing in public."

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