A D.C Superior Court jury yesterday awarded $180,000 to the family of a former District police officer who used his service revolver four years ago to kill his father-in-law and would his estranged wife and young son.

Attorneys for the family argued that the District government was negligent by not removing the officer from the police force after it was informed that the officer had threatened his wife prior to the shooting incident.

The officer, John Henry Morgan Jr., 31, was convicted in 1975 of first degree murder in the 1974 death of his father-in-law, Elton E. Pinkney, 64, and two counts of assault with intent to kill. A District police lieutenant was also injured during the incident.

The largest single share of the award -- $90,000 -- went to Morgan's estranged wife, Garnett P. Morgan, 31, who was hit with two bullets. Her son, John Keith Morgan, 10, was awarded $15,000, and her mother, Mary Beatrice Pinkney, was awarded $75,678 as the surviving heir of Elton Pinkney.

The District government can file motions to overturn or reduce the fury's award and then has the right to appeal the verdict.

The case hinged on whether the police department knew that Morgan had threatened to shoot his wife before Nov. 7, 1974, when he walked into his father-in-law's southeast Washington home and began firing a gun.

Mrs. Morgan testified that she told Morgan's superiors that she had been threatened and that no investigation of her complaint was made, according to court records and attorneys in the case.

The police, though, testified they received no such complaint from Mrs. Morgan, attorneys said.

This is one of an increasing number of cases in which citizens seek to hold the government liable for the actionsd of its employes. The court decisions have been mixed. While this is not the first case in which a city government has been found negligent for keeping an officer on the police force when there were questioms raised about the officerhs behavior, other court decisions and administrative acts have forced police departments to retain officers they tried to dismiss.

In the Morgan case, for example, a police department trial board recommended in 1970 -- four years before the shooting -- that the officer be dismissed from the force after he pladed guilty to five charges that were unrelated to violent acts.

But then Mayor Walter E. Washington overruled the trial board'srecommendation and Morgan remained a police officer until he resigned after the shootings.

The civil trial before Superior Court Judge Fred B. Ugast took six days. The 12-member jury returned its verdict at 11:55 a.m. yesterday after considernig the case through the morning.