A 51-year-old Baltimore County sex offender has been charged with first-degree murder in the shooting of a death row inmate's son in Northwest Baltimore last August.

City police said Robert D. Saunders, who pleaded guilty to a child abuse charge in 1999, was arrested Thursday at his parole and probation officer's office. Police served a search and seizure warrant on his listed address and found that Saunders did not live there and used it only for the sex offender registry, according to Anthony Guglielmi, the department's chief spokesman.

Saunders was charged with first-degree murder in the killing of Nolan Evans, 40, who was shot Aug. 25 at Garrison Boulevard and Liberty Heights Avenue.

Evans was the son of death row inmate Vernon Evans, who was convicted in the 1980s of killing two people, including a federal witness in a drug case.

Nolan Evans had troubles of his own, serving time for being a felon in possession of a handgun. He was charged separately with murder and was acquitted by a jury.

Details of how Saunders was linked to the killing were not immediately available.

Court records indicate that Saunders had been convicted several times for failing to register a current address with the state sex offender registry. In 2007, he was sentenced to three years in prison for failing to register, with one year and six months suspended, followed by three years of supervised probation.