In the early morning darkness of Feb. 12, 1979, two police officers, their weapons drawn, crouched outside an apartment in southern Fairfax County, waiting for a man they believed to be an armed murder suspect.

Suddenly a shot rang out from inside the apartment, and moments later a man and woman dashed outside. The fleeing man died in a burst of police gunfire, falling into the arms of the woman.

The officers, it turned out, had shot the wrong man, Stanley Hughes, 21, who, with his mother, was racing to escape the apartment and the murder suspect, Kenneth Eugene King, 33, who had just committed suicide inside.

"I felt like I had died along with him," said Hughes' mother, Naomi, on the witness stand yesterday in the opening day of testimony in her $10 million lawsuit in U.S. District Court in Alexandria.

Hughes cried as she recounted the events that led to her only child's death and the civil damage suit against Arlington and Fairfax counties, their chiefs of police and four individual police officers.

Police officials disagree with Naomi Hughes on what occurred that winter morning.

"I thought that she had been shot and that the subject behind her was shooting at her," testified Fairfax Sgt. Walter Blankenship, who fired the first shot at the unarmed man.

Naomi Hughes' lawyer, William B. Moffitt, charged yesterday that Stanley Hughes' death was caused by "reckless . . . [and] arbitrary" action actions on the part of the police. The officers did not intentionally kill Hughes, but "things needed to be done to protect life . . . on that scene that were not done," Moffitt said in his opening statement.

Moffitt said he intends to prove that Fairfax and Arlington police officers receive inadequate training in the use of firearms in tense situations.

Defending the actions of the officers, defense lawyer Jack L. Gould said police receive "very adequate" training -- "in excess of that required by state law."

The defense is arguing that under the circumstances, especially upon hearing a shot fired from inside the apartment, the police acted "reasonably" when they discharged their weapons.

"It was a life or death decision," Gould told the jury in his opening remarks. "The officers made that decision to save Mrs. Hughes' life and to save their own lives."

Hughes and the officers differ about what she yelled when she ran from the apartment. Hughes testified she shouted over and over, "He [King] shot himself!" as she ran outside.

Blankenship testified: "I have no idea what she was screaming."

Acting on a tip from an anonymous source, a total of six police officers had gone to Hughes' Fairfax apartment at 3332 Lockheed Blvc. to arrest King for alegedly shooting and wounding a relative in Arlington. The officers also knew that King was a suspect in the killing of another relative.

Hughes testified yesterday she became frightened when she learned that police were hunting King. Hughes, who is divorced, said she had dated King on and off for several years, and he was living with her at the time of his death.

When police telephoned her, she said she lied and told them King was not in the apartment. King stood next to her and told her what to tell the police, she said.

The defense contends that Hughes lied because she was harboring King from the police.

Hughes testified she told police the only person with her was her son and said police never asked how old her son was. Defense lawyers said the officers assumed her son was a child.

Blankenship said he remained calm throughout. "I don't feel I ever lost my judgment," he testified. A total of four shots were fired by the two officers. Blankenship fired three times and Arlington Cpl. Kenneth Madden once.

Stanley Hughes died from two gunshot wounds. Hughes' lawyer, Moffitt, said ballistic tests failed to determine who fired the fatal shots. Two other Arlington officers, Lt. David Reiten and St. Arthur Christiansen, are named as defendants. They were at the scene but did not fire their weapons.

Fairfax police conducted their own investigation into the shooting and cleared the officers of violating police procedures.