The killing of U.S. Army Maj. Arthur D. Nicholson Jr. by a Soviet sentry in East Germany last month was a dastardly deed. But the details on how it happened are still confusing.

Facts about the incident have been seeping out, and the stories keep changing. This points to a continuing problem for the media -- giving heavy play to a news event when facts are few, and then dealing with new and different details when the news impact has diminished. The problem in this case was even more awkward because it involved reporting facts that challenged initial statements from the U.S. government.

The first report by a State Department spokesman on March 25 said Nicholson was 300 to 500 yards outside a permamently restricted area when he was shot without warning b a Soviet soldier. The same Post article said the Russians charged that the major had entered a restricted Soviet military installation despite warning signs in Russian and German and was caught photographing combat equipment.

The next day's story added to the Soviet charges. A Moscow dispatch said Nicholson had secretly approached a storage facility, opened a window and begun taking photographs. Obviously this meant he was closer than 300 to 500 yards.

On March 28 The Post reported that the Reagan administration had given ground and now acknowledged Nicholson was attempting to photograph Soviet military equipment in a garage- like storage shed. The story also noted that administration officials did not dispute the Russian statement that Nicholson had opened a window and was taking pictures when discovered.

The American and Soviet versions were now coming closer together, but then the administration officials took a new position -- that the shed was not in an area permanently restricted by the Soviets, but that a former "off limits" prohibition had been lifted in February.

But the next day The Post, citing Pentagon officials who interviewed Nicholson's driver, Sgt. Jesse Schatz, reported an entirely different version -- Nicholson never reached the storage shed he intended to investigate, did not open a window or take a picture of the interior. And now, "despite earlier statements, officials at the State and Defense departments said the site of the killing had not been designated as a temporarily restricted area by the Soviets at any time in the recent past."

Last week The Post printed a Reuter dispatch from Bonn revealing a new Russian attitude -- after being defended by his government for several weeks, the sentry was now facing disciplinary measures and might be court-martialed for using excessive force.

This story was on page 28, a bit more buried than the front-page stories of late March. And there were no attempts to try to reconcile the several changing versions of what happened. I did not find clarification in other papers either.

Maj. Nicholson is dead; that cannot be changed. But I believe readers should be helped through these conflicting reports. The new assistant managing editor for national news, Robert Kaiser, told me further reporting is planned.

This episode stands in contrast to the way The Post reported the killing of two CBS News employees by Israeli tank fire in southern Lebanon last month. The first report on March 22 quoted the head of CBS News as charging that the shooting was unprovoked and deliberate. In the next day's story CBS rejected the Israeli defense that the two were fired upon because they were in the midst of a group of guerrillas.

CBS then sent Ernest Leiser, a CBS News vice president, to Israel to investigate. On March 25 he told the press the killing could have "simply been a tragic error." Two days later Edward Walsh, The Post's correspondent in Israel, in a 11/2-column story, reported that Leiser "came to the conclusion that it was not somebody shooting deliberately at a camera crew. It was somebody shooting at what they thought were armed men about to fire at them."

The paper dealt with initial reports that were in conflict, followed through and gave much space to a report that varied from the first story. While the matter was handled professionally, the clarifying story was on page 25.

The Nicholson story still has several loose ends. Whether it is possible to give readers a consistent report on the circumstances of this American's sad death amid volatile U.S.-U.S.S.R. relations remains a question.