PITTSBURGH (AP) _ A teen-ager charged with killing the son of a community activist is suspected of killing two other people and wounding up to six during a four-month robbery spree, police said Wednesday.

Anthony Martin, 18, cruised streets accosting his victims, including two retired men working as taxi drivers, Homicide Cmdr. Ronald Freeman said.

``They're generally older, honest, hard-working guys,'' Freeman said. ``They don't anticipate this.''

One victim, Richard Hall, 66, was missing for 25 days before detectives found his decomposing body Wednesday on a desolate hillside.

Martin was to be charged in Hall's death Thursday, pending an autopsy, detectives said.

Martin has been jailed without bond since Monday, when detectives found him not far from where 26-year-old Lutual Love Jr. _ son of a local community activist _ was shot to death last Friday.

Martin was charged with Love's death and became a suspect in the shootings and robberies of about a dozen other people or businesses.

One victim, Chatham College student Michael Knox, 22, was shot in the head Sunday night after an assailant made him withdraw money from a bank machine. He remains in critical condition.