During the 22 years he spent in
prison after being convicted of killing a Boston
police detective, Sean Ellis believed there was something suspicious about the officers who led the murder investigation.
It would take years of digging and scores of public information requests from his attorneys to uncover evidence that several officers investigating the 1993 murder case were involved in criminal activity — information that wasn't shared with the defense.
Defense attorneys have long run up against a brick wall when trying to discover whether an officer has credibility issues that could set their client free.