For more than a decade, one question remained unanswered: Who killed Irasema Chavez? Now, Arlington police and the FBI say advances in DNA technology have led to a major break in the 2012 cold case. Authorities announced the arrest of 42-year-old Mayra Velasquez, who is charged with capital mu rder in the stabbing death of Chavez. Chavez, 33, was found stabbed more than 100 times inside her Arlington apartment in 2012. Investigators spent years examining surveillance video showing a person walking into Chavez’s apartment, but the case eventually went cold. Police said the breakthrough came after partnering with the FBI through its Investigative Genetic Genealogy program, which led investigators to Velasquez. Dr. Alex Del Carmen, a criminologist who is not involved in the investigation, said DNA technology has advanced significantly since the case began. “The pool of the DNA sample was very limited. The technology was very expensive. It was far from being perfect and it was delayed,” Del Carmen said of DNA technology available in 2012. He said modern DNA analysis gives investigators more information than was possible years ago. “It’s not based on a guess. It’s not based on a witness that may have seen something. It’s based on the DNA that already tells there are certain components of that DNA that are typical of people that may have green eyes or may have brown eyes,” Del Carmen said. Del Carmen said he expects advances in DNA analysis will continue helping investigators solve cold cases. “We’re fascinated by in the media and in the public realm because we just love the idea of justice finally being served. But I do believe that in many cases the reason for is because DNA sampling has become so much better,” he said. The arrest marks a significant development in a case that remained unsolved for 14 years. ...read more read less