Durham, N.C. — Durham County prosecutors on Friday dismissed a first-degree murder charge against one of two men accused of killing a Duke University graduate student more than five years ago.

Stephen Lavance Oates, 24, had been charged in the Jan. 18, 2008, shooting death of Abhijit Mahato.

Durham police arrested Oates five days after Mahato was found dead inside his apartment near Duke, and prosecutors had said that ballistics evidence linked him to the crime.

The 9mm gun used to kill Mahato matched one used in two robberies where victims were shot in the legs. One of the victims identified Oates as the gunman.

Prosecutors said Friday that witnesses have since changed their stories, leaving them with insufficient evidence tying Oates to Mahato's death.

The dismissal means that Laurence Alvin Lovette Jr. is the only person charged in Mahato's death.

Lovette, 22, is already serving time for the March 5, 2008, shooting death of Eve Carson, a former student body president of the University of North Carolina at Chapel Hill.

Oates has always maintained his innocence in Mahato's death, and prosecutors previously have acknowledged that Lovette told a witness he killed Mahato with someone named Phillip.

"He and some of his buddies were robbing people with BB guns, not a real gun," said Oates' defense attorney, Mark Edwards. "I think what happened was, it was just a bad (identification) for the Hispanic guy that got shot, and whatever happened, Steve somehow got implicated in it, and police felt it was the same gun and charged him with Mahato.

"There's really nothing to tie him to it," Edwards said.

Oates has been out of jail since last May, and his attorney said he is working and staying out of trouble.

He is expected back in court in March to face four counts of assault with deadly weapon with intent to kill and one count each of robbery and obtaining property by false pretense in connection with the robberies.