NEW YORK — In a surprising development, a judge has overturned one of the convictions in the high-profile murder case of Jam Master Jay, the legendary Run-D.M.C. DJ.

Almost two years after a jury reached a guilty verdict, Judge LaShann DeArcy Hall has nullified the murder conviction of Karl Jordan Jr. The decision was based on insufficient evidence regarding Jordan’s alleged motive to murder Jason Mizell, famously known as Jam Master Jay.

During the trial, a key eyewitness claimed to have seen Jordan, who is also Mizell’s godson, shoot the renowned DJ in his Queens recording studio on October 30, 2002. This testimony had been central to the prosecution’s case.

However, Jordan’s defense team contended that the prosecution failed to prove that he had a motive for the crime, challenging the narrative that the killing was a vendetta over a botched drug deal.

But Jordan’s lawyers had argued that the evidence didn’t support prosecutors’ claims that he killed Jam Master Jay, as revenge for a failed drug deal.

“We are really happy for Mr. Jordan and his family that justice was served,” attorney John Diaz said in an email.

Jordan had not yet been sentenced on the murder charges, but remains behind bars awaiting trial on drug charges from many years after the killing.

The U.S. Attorney’s Office is reviewing the decision.

Separately, the judge said the government proved the motive in the case against co-defendant Ronald Washington; so, his motion for an acquittal was denied.

Mizell worked the turntables in Run-D.M.C. as the group helped hip-hop break into the pop music mainstream in the 1980s with such hits as “It’s Tricky” and a fresh take on Aerosmith’s “Walk This Way.”

His killing became one of the hip-hop world’s most elusive cases.