Durham, N.C. — An attorney representing one of two men charged in the slaying of a Duke University graduate student last year says his client did not shoot the victim and that witnesses who led investigators to him are now changing their stories.

That is the conclusion of a defense investigation into the Jan. 18, 2008, slaying of Abhijit Mahato, attorney Mark Edwards told a judge during a bond hearing Monday morning.

Edwards' client, Stephen Lavance Oates, 20, of 2303 Anthony Drive in Durham, faces a number of charges, including murder and robbery with a dangerous weapon, in connection with Mahato's death.

Mahato was found dead inside his Anderson Street apartment, just off Duke's campus. An autopsy found he died from a single bullet fired directly at his head.

Edwards also said Monday that he believe prosecutors are basing their case on two victims from other robbery cases who initially told investigators that Oates shot them.

"My investigator has gone out and spoken with both of those individuals, shown them pictures of Mr. Oates, and both of them are pretty adamant that he is not the person that shot them at the time," Edwards said.

Durham County District Attorney Tracey Cline said at least one of the witnesses was afraid to give a statement and that she would not be surprised if they did not tell the truth to a private investigator working for the defense.

Meanwhile, Superior Court Judge Allen Baddour set Oates' bond on the charges at $10 million, at Cline's request.

Cline has indicated she won't seek the death penalty in the case against Oates.

Prosecutors suspect Oates and another man, Laurence Alvin Lovette Jr., 17, robbed Mahato at gunpoint and, according to court records, stole $200, a wallet, an iPod and a cell phone from him.

Police arrested Oates five days after the shooting, following a multi-county, high-speed chase.

Less than two months later, authorities arrested Lovette on a murder charge in the shooting death of another local college student, University of North Carolina-Chapel Hill senior Eve Carson.

According to an arrest warrant, Mahato's cell phone helped police link Lovette to the crime when he was arrested in Carson's death.

Cline has also said in previous hearings that police found Mahato's iPod on Lovette and that investigators were not sure which suspect shot Mahato.

Mahato, originally from Tatangar, India, was studying for an engineering doctorate degree in computational mechanics at Duke’s Pratt School of Engineering. He was in his second year.