A Winston-Salem Journal editorial calls on other states in the country to pass laws preserving DNA evidence as North Carolina has done. Currently only 25 states and the District of Columbia have such laws. The editorial points out that lost or destroyed DNA evidence in one state can hamper another state’s efforts to get innocent people out of prison and apprehend the real criminals.
For example, say detectives in North Carolina who've re-opened a murder case in which someone has been convicted are looking for a match for DNA evidence found at the crime scene. The real killer's been in prison for an unrelated crime, but it's in a state that's lax on preserving such evidence. So his DNA isn't in the system. The killer stays free, and an innocent person stays in prison.
That's probably already happened numerous times. And it will probably happen a lot more. For example, in New York, a law that would have provided for DNA preservation died in the State Assembly in June, according to USA Today. Some states have shown a "shocking" disinterest in keeping DNA, said Larry Pozner, the former head of the National Association of Criminal Defense Lawyers. "Innocent inmates are going to die in prison," he said.
The editorial does see some reason for hope in at least two states. Colorado and Arizona are both working towards legislation to preserve biological evidence.