According to the University of Michigan's National Registry of Exonerations, over 600 convictions have been overturned based on DNA evidence. Considering the stakes of a death penalty case, you would think that DNA testing, if available, would be standard practice. It's not.
So what if a prosecutor doesn't want to submit evidence to testing? Do death penalty defendants have a right to force law enforcement to conduct DNA testing?
According to the Supreme Court, they do not. While criminal defendants have a right to access the evidence against them prior to trial, in 2009 the Court announced that there is no constitutional right for someone who has already been convicted of an offense to get access to the prosecution's evidence to perform DNA testing.
That said, there are still some legal options available for post-conviction DNA analysis. Most states have procedures in place to allow for DNA testing following a conviction, in certain situations.
In general, most states require a showing of conclusive proof that the new DNA evidence would have altered the result of the first trial, but the exact standard will differ among jurisdictions. The differences between the standards are often subtle, but can have a huge impact on the outcome of an application to reopen a case for genetic analysis.
Applicants must typically meet other requirements as well. Most often, there is some sort of time limit on how soon the inmate must apply for testing after the discovery of new evidence. Some states accept new evidence for some time after it's uncovered, but other states are fairly strict and require that inmates apply for DNA analysis very quickly after they learn of new evidence.
Two years after its prior decision, the Supreme Court concluded that a denial of access to prisoner DNA testing can be litigated under section 1983 as a civil rights claim.
The issue has resurfaced in the case of Rodney Reed, a man convicted of kidnapping and murder in 1998. He has been asserting his innocence all along, claiming that DNA testing of evidence found at the murder scene will exonerate him. But, thus far, prosecutors have opposed testing, even of the murder weapon.
Reed is scheduled to be executed next month, and has appealed to the Supreme Court, arguing that executing him without conducting DNA testing is a violation of his constitutional rights. A decision in that case is expected soon.