A federal jury yesterday cleared four Northern Virginia police officiers of liability for their actions during a stakeout in which police e shot to death the wrong man.

The six-member jury in U.S. District Court in Alexandria deliberated for about 2 1/2 hours before reaching its verdict in the $10 million wrongful death suit brought against the police by the mother of Stanley Hughes, 21, who was killed Feb. 12, 1979.

Although police shot Hughes instead of a murder suspect they were seeking, the jury found that the officers acted reasonably and did not exhibit gross negligence.

When police surrounded the apartment of Hughes' mother in the darkness of that early February morning, Hughes and his mother Naomi dashed from the apartment moments after a shot rang out from inside.

Police shot Hughes, thinking he was the murder suspect, but the real suspect, Kenneth Eugene King, 33, had just committed suicide inside the apartment.

"It's a tragedy for everybody," defense lawyer Paul F. Sheridan said after the verdict. "Those guys really care," he said, referring to the four officiers.

"There's no way to describe how I felt," Arlington Cpl. Kenneth Madden testified at the trial. Madden, one of the two officiers who shot at Hughes, said he cried when he realized the wrong man had been slain. "Never in my life before have I fired a weapon on another human being," said Madden, 35, a 14-year police veteran.

William B. Moffitt, Hughes' lawyer, said he was disappointed by the verdict. He said the officers benefited from being tried by an all-white jury in Northern Virginia.

Hughes was black. All four officiers are white.

"Welcome to Northern Virginia," Moffitt said, "where a statue of a Confederate soldier stands, facing south . . . right in front of the federal courthouse. I think if we had tried this case elsewhere we would have done all right."

Moffitt said whites lack a complete awareness of the way police treat blacks. "It's purely a lack of sensitivity," he said.

Moffitt said a key moment was the instruction to the jury by U.S. District Judge J. Calvitt Clark Jr. The judge told the jury that to find in the favor of Hughes it would have to conclude the officers showed "gross negligence" -- an utter disregard for human safety during the incident.

In rejecting Moffitt's plan to set aside the verdict, Judge Clark said "the jury's verdict is clearly in accordance with the evidence."

When the officiers went to Hughes' apartment at 3332 Lockheed Blvd. in the Rte. 1 corridor of Fairfax County, they had a warrant to arrest King for alledgedly shooting and wounding a relative in Arlington. The police also knew that King, who was considered "armed and dangerous," was a suspect in the killing of another relative.

The four officiers cleared by the verdict were Fairfax Sgt. Walter Blankenship and three Arlington officiers, Sgt. Arthur Christiansen, Lt. David Reiten and Madden.

Fairfax and Arlington counties and their two police chiefs, were dismissed as defendents in the suit by Moffitt before the case went to the jury.