More than 20 years ago, in separate cases, two men were convicted of injuring children: Andrew Roark, from Dallas County; and Robert Roberson, from Anderson County. Both cases hinged on a theory known as “shaken baby syndrome” and “abusive head trauma.” The same expert witness testified for the prosecution in both trials. New research shows, however, that such evidence of shaken baby syndrome is not as reliable as courts, police and medical professionals had believed.