OAKLAND -- Partially blinded by a blast of pepper spray fired at him by a robber, a 67-year-old Oakland man was still able to grab a pocketknife and stab the suspect, who was arrested later at a hospital, authorities said Thursday.

A second suspect, who yanked a gold chain off the man's girlfriend's neck after pointing a gun in her face, is still being sought, police said.

The stabbed suspect, identified by police as Tarnell Cobbs, 19, of Oakland, has been charged with one count of attempted armed robbery and one count of armed robbery. He is still hospitalized and has not been arraigned yet.

He has refused to talk to investigators, and police believe he might be responsible for other similar robberies.

The violent confrontation happened about 8 p.m. Nov. 27 outside the man's home, on East 26th Street. The couple had just driven up after visiting a relative.

The 67-year-old man was getting out of his car when Cobbs approached him in the driveway, pepper-sprayed him in the face and demanded his wallet and cash, Officer Omar Daza-Quiroz said.

The man acted as though he was taking his wallet out of a back pants pocket but instead grabbed his knife from its sheath and stabbed Cobbs in the abdomen, police said.

At the same time the other suspect was robbing the man's 50-year-old girlfriend at gunpoint of her gold necklace about 15 feet away.

Daza-Quiroz said Cobbs did not get anything from the man and that he and the other suspect fled in a car.

Police alerted hospitals and found out a man later identified as Cobbs had arrived at Highland Hospital for treatment shortly after the robbery. Neither the knife nor pepper spray canister were recovered, police said.

The victim later identified Cobbs as his attacker, police said.

Authorities said the man who was pepper-sprayed was acting in self-defense and will not be criminally charged.