From WSJ -
"In their reinvestigation, prosecutors found a document in the state's trial file detailing one person's statement, saying that one of the suspects had motive to kill Ms. Lee and had threatened her in the presence of another person. The suspect said "he would make her [Ms. Lee] disappear. He would kill her," according to the court filing.
That information was never given to the defense, the filing said. Prosecutors are required by law to give defense counsel exculpatory evidence upon request.
The reinvestigation also revealed that the grassy lot where Ms. Lee's car was found in Baltimore was located behind a house that belonged to one suspect's relative."