The man convicted last month of second-degree murder in the slaying of North Carolina honors student Phylicia Barnes will receive a new trial after a key witness’ testimony was deemed not credible.

Michael Maurice Johnson was scheduled to be sentenced March 20 after a Baltimore jury found him guilty last month. Instead, Judge Alfred Nance approved the defense’s motion for a new trial said Sydnee Wilson, spokeswoman for the state’s attorney’s office for Baltimore City.

She said she could not release any additional information about the trial, as it is on-going.

“We are disappointed in the judge’s decision, but we look forward to the new trial in which we will be able to present the evidence and testimony we believe establishes the defendant’s guilt beyond a reasonable doubt,” State’s Attorney Gregg L. Bernstein said in a statement on March 20.

Johnson, the boyfriend of Barnes’ half-sister, was acquitted of first-degree murder, but found guilty of the lesser crime. The 11-day trial included more than 17,000 pages of evidence on both sides, including a graphic 16-minute tape showing Barnes, her half-sister Deena Barnes, Johnson and his younger brother Glenton Michael Johnson engaging in sexual acts after going streaking together.

Johnson was convicted of killing Barnes in her sister’s Baltimore apartment, where she had been visiting, and disposing of her body in a plastic tub.

Nance opted for a new trial after testimony from key witness for the prosecution, James McCray, who claimed he saw Barnes’ body and was asked to help him dispose of it, was deemed not credible.

Barnes disappeared in December 2010, and gained national media attention after local law enforcement initially failed to identify the teen as a missing persons case. Barnes came to Baltimore to visit her half-sister, who she had reconnected with via the Internet.

After an intense search following her disappearance, her body was found in the Susquehanna River in northeastern Maryland a year later.