Transcript for Texas police use a controversial type of DNA test to identify a suspect
world is watching. Now to a case in Texas. A woman was stabbed to death. The case unsolved for more than a year. The police employed a tactic called familial testing. Here's ABC's Marci Gonzale Reporter: After more than a year and a half of painstakingly trying to figure out who brutally murdered natliya shall on mother's day, 2016, tonight, a suspect is finally behind bars. Tracked down police say using a controversial type of DNA testing. This is pretty rare. Reporter: Police say the killer's DNA was found at shal's home in Baytown Texas where she was stabbed to death but there was no match in the database. So, investigators tried "Familial" testing, which searches for DNA markers genetically similar to other violent offenders. It led them to an inmate whose brother then became the prime suspect. Our detectives were able to identify a person of interest in the case as 29-year-old Byron Collins of Baytown. Reporter: Police say then using DNA from a discarded cigarette, they were able to link Collins directly to the crime scene. You are charged with capital murder. Reporter: Familial DNA testing is only used in several states and some call the method an invasion of privacy. But it has been pivotal in some high profile cases including, in California where it was used to help capture the serial killer known as the "Grim sleeper." And as for the suspect in Texas, he has not yet entered a plea,
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