When someone is accused of sexual assault, the case often involves eyewitness testimony supported by DNA analysis or other scientific evidence. Particularly when there are problems with the eyewitness testimony, prosecutors often rely on DNA or other scientific evidence to support the victim's story.
But what if the DNA evidence is inaccurate? Worse, what if prosecutors try to shore up weak cases with junk science?
Challenging improper or inaccurate evidence is a common undertaking for the Innocence Project, which works to free the wrongfully convicted and to fix the problems in our justice system that lead to these wrongful convictions.
In a recent case, the Innocence Project demonstrated that junk science was a big part of what led the so-called "San Antonio Four" to be convicted of raping two little girls, then 7 and 9, while on a drug- and alcohol-induced rampage in 1994. The junk science there didn't involve DNA, however.
The San Antonio Four were lesbians. The two girls were the nieces of one of the Four, Elizabeth Ramirez, and had been vacationing at her home. The girls' stories seemed fantastic and unbelievable -- and they changed over time.
Backing up their claims was a doctor who offered testimony about hymen trauma -- using a now-debunked theory.
All four were convicted of indecency with and aggravated sexual assault of a child. Three were sentenced to 15 years in prison. Ramirez, considered the ringleader, was given 37.
The Texas Court of Criminal Appeals recently exonerated the San Antonio Four, ruling that "with the lack of reliable forensic opinion testimony corroborating the fantastical allegations in this case, no rational juror" could have convicted them.
"Those defendants have won the right to proclaim to the citizens of Texas that they did not commit a crime," reads the majority opinion. "That they are innocent. That they deserve to be exonerated. These women have carried that burden. They are innocent. And they are exonerated. This court grants them the relief they seek."
Rivera, Kristie Mayhugh and Cassandra Rivera were released in 2013 after their legal team reached an agreement with the Bexar County District Attorney. Anna Vasquez received parole in 2012. This ruling makes them eligible for compensation under the law of that state.