An argument led to the bludgeon deaths Tuesday of Mary E. Harben, 71, and her son, Joseph E. Stanton, 54, both of 5402 Morton Pl., in the Beacon Heights section of Riverdale, Prince George's County police said yesterday.

Officers were summoned by neighbors who reported the presence of a possible prowler about 7:30 p.m. Officers said that when they arrived they found Stanton's body on the doorstep of the neighbors' home, and that of his mother inside the home across the street. Investigators said both victims had been beaten with a blunt instrument.

Moments after police arrived, they caught a suspect who, they said, was seen running from the area. The man, Michael Meador, 28, was charged with two counts of murder. Meador, who lives at 502 Patauxent Rd., Odenton, was jailed without bond.

Police said that Meador, a drywall installer, was an acquaintance of Stanton's son, who also lives in the Morton Place house but who was not at home at the time of the deaths.

Police said their investigation indicates that Meador had been in the house with Stanton and Harben, and that an argument developed. They believe that Stanton had gone to the neighbors' home to get help after he and his mother had been attacked.