With six weeks left in the year, Prince George's County set a record yesterday of 87 homicides, surpassing its 1982 toll of 86 slayings, police said.

The three killings yesterday included two shootings, one in

Forestville and a drug-related slaying in Landover, said police Capt. Jack San Felice. In the third death, a Bowie woman was fatally beaten during a domestic dispute, police said.

The year's 87th slaying victim, identified as Ernest William Johnson, 25, of Northwest Washington, was fatally wounded about 3:50 p.m. after he and another man entered an apartment at 2110 Brooks Dr. in Forestville, police said. He was shot during an apparent argument there, police said.

Johnson collapsed outside the apartment and was taken to Malcolm Grow Hospital, where he died at 5:16 p.m. Police were searching for the apartment's occupants, who fled immediately after the shooting, to determine why the incident occurred.

Earlier in the day, 28-year-old Zachary Valdez Daggett of 6915 Kent Town Dr., Landover, was shot to death in the 2400 block of Virginia Avenue in Landover when a drug deal apparently went sour, police said.

Police said Daggett was approached by two people asking to buy drugs around 1:30 p.m. yesterday. After one of the men pulled a handgun and demanded drugs and money, Daggett was shot as he tried to flee, San Felice said.

The assailants fled in an unidentified car, police said. Daggett was pronounced dead at the scene.

In another incident, police say a 52-year-old Bowie woman was beaten to death during a dispute with her son, who was hospitalized in serious condition.

Anne Catherine Thaler was pronounced dead about 7:20 a.m. at her home in the 8300 block of Cowan Avenue, a police spokeswoman said.

Police said her 28-year-old son, Martin Thaler, pulled a knife on her during an argument. She was knocked to the floor and beaten on the head and chest, police said.

Martin Thaler was hospitalized in serious but stable condition with a stab wound to the abdomen. Police said an investigation was continuing.

In addition to the homicides, police were investigating the death of an unidentified man whose body was found in the 3900 block of Rhode Island Avenue in Mount Rainier, a spokeswoman said. The man was discovered face down on the sidewalk about 7:30 a.m. by a resident walking a dog, she said.

Authorities are awaiting autopsy results, the spokeswoman said.