Somebody new (Becky Feldman) to the prosecution office opened the case files and found notes about a suspect that was never made public and unknown to people even in the DA's office. Turns out there are 2 suspects who were never properly ruled out. One of them was implicated to detectives by 2 different phone call tips months apart and he had motive to kill her. He was quoted as saying he would make her disappear and he would kill her. Feldman looked into him and found he had the opportunity, motive, and means to commit the crime. These suspects have relevant criminal histories and connections to the location where the victim's car was found.
It appears Adnan's lawyers were never made aware of these phone calls, and this is a Brady violation.
The investigators also don't trust Jay's testimony, which was my insurmountable hangup with the case. At the time, they claimed the cell phone records backed up Jay, so you didn't have to fully rely on his testimony, but now the state is saying they can't claim the cell phone records back him up. One of the detectives who interviewed Jay and was a big part of the investigation has since been caught in egregious misconduct, having other convictions overturned.
Feldman is the one who filed the motion to vacate.