A DNA expert took the stand yesterday in the Baltimore trial of two men accused of killing three young relatives and gave jurors a science lesson as prosecutors prepared to introduce evidence that they say ties the defendants to the killings.
Lynnett Redhead, a criminalist with the city Police Department, extracted and analyzed DNA from blood stains and skin cells in the case. Using slides and a pointer, she stood before the jury box and defined some of the terminology, such as alleles and double-helix strands, that jurors are likely to hear over several days of her testimony.
Prosecutors said in their opening statements that two blood-stained pairs of blue jeans were worn by Policarpio Espinoza, 23, and Adan Canela, 18, who are accused of slashing the throats of Lucero Espinoza, 8, her brother Ricardo, 9, and their male cousin, Alexis Espejo Quezada, 10.
DNA from skin cells found inside the jeans is consistent with the defendants' genetic profiles, prosecutors have said.
Both men are on trial in Baltimore Circuit Court on charges of first-degree murder and conspiracy to commit murder in the May 27, 2004, killings in Northwest Baltimore. Espinoza is the children's uncle and Canela is a cousin.
Redhead began by explaining DNA to the jury as a "blueprint for our makeup."
She then explained some of her findings in the case. She compared swabbing of blood and other material found on evidence at the crime scene, in the defendants' Baltimore County home and in the car they drove to the DNA profiles of the slain children, three parents of the children and Espinoza and Canela.
She has testified that blood stains on a 17-inch meat-cutting knife found outside the crime scene are consistent with DNA from all three slain, as were drops of blood on cups in the kitchen sink there.
Redhead has yet to discuss the jeans and two blood-stained work gloves police say were in the a car the defendants used.
Redhead's scientific testimony yesterday followed a morning lesson in engineering by a Nextel cellular telephone company network engineer.
Bruce Levine said that he was able to determine about where Policarpio Espinoza's cell phone was when calls were placed from it or received on it throughout the day the children were killed.
Six calls showed his phone would have been in the Northwest Baltimore area where the children lived in a Fallstaff apartment. Espinoza lived in Baltimore County on Bedford Road a few miles away.
Espinoza's phone records indicate that his cell phone was never in Fells Point or Bel Air the day of the killings. Espinoza sporadically worked construction jobs in Bel Air and told police he had been in Fells Point when he learned that "something tragic" had happened to the children.
Espinoza's phone did not receive any calls, and none were made, between 2:55 and 4:30 p.m. May 27, the records show. Police believe the children were killed about 4:30 p.m. that day. Seven phone calls on Espinoza's phone that day were to or from the cell phone of Guadalupe Juarez Hernandez, the wife of Victor Espinoza Perez and stepmother of Adan Canela.
Canela's defense attorney, James Rhodes, has told jurors that Hernandez had learned that her husband had a romantic interest in Alexis Espejo Quezada's mother.