Alexandria police said yesterday they are still trying to unravel conflicting stories of how a D.C. government worker shot and wounded two teen-agers he claims were trying to rob him in his posh, high-rise apartment Saturday.

The incident left two youths critically injured. One of them survived a fall from the apartment's eighth-floor window after being shot in the hand. A second youth was critically injured by a gunshot wound to the head. A third, who escaped the gunplay by climbing down a telephone cord to a seventh floor apartment, was uninjured and released yesterday to the custody of his parents.

Although investigators believe that a robbery attempt may have led to the shooting, they have filed no charges.

"We have gotten several versions of what happened yesterday and we're just trying to get to the truth," said Alexandria police Sgt. Al Levesque yesterday. "I don't want to get into specifics, but we're going to have to dig a bit deeper on this one."

The incident occurred in the eighth-floor Landover House apartment of Ronald Irving Taylor, a 33 year-old D.C. government official with a doctorate in psychology from New York University.

In seeking to reconstruct Saturday's event, police have been given conflicting accounts of what the three youths were doing in Taylor's apartment and how they came to be there.

Taylor and a male roommate steadfastly cling to the attempted robbery version. Parents of one of the injured youths said yesterday, however, that the youths were invited upstairs after announcing their arrival in the lobby.

Although Taylor told a reporter Saturday night that he did not know his alleged assailants, the parents of the youth that leaped through the eighth-floor window vehemently deny this. In an interview yesterday, Levesque added that Taylor "from the start" indicated that he had previously known at least one of the teen-agers.

The 17-year-old who survived the eight-story fall apparently had run away from home on New Year's Eve in 1979, according to his mother, and was not seen again by his parents until after the shooting incident. Prior to this, a student at D. C.'s Woodrow Wilson High School in 1979, the youth had worked in the District Building in a clerical position in the city's summer jobs program, she said.

But the youth, according to his father, "has been in the streets" for the past year, reportedly living with friends in the Mount Pleasant area of the city. Both parents said that they have no idea why their son, and the two other youths, went to Taylor's apartment Saturday. The girlfriend of the youth said yesterday that the three had gone there "to get money."

According to Taylor's roommate, one youth arrived alone at the apartment and behaved strangely as he talked with Taylor in a bedroom. Said the roommate, "I think Ron was lucky; the kid was acting strange. When [the youth] left the bedroom," ostensibly to get a glass of juice, "[Ron] put the gun in his pocket. The three of them were standing there when he came out."

According to the roommate, who was not present during the incident, and a source, the youths announced that it was a robbery and demanded money. Taylor then defended himself, according to the source, when he saw that the "rifle" -- concealed by one of the youths with a coat -- was nothing more than a baseball bat and believed that he was about to be bludgeoned to death.

Taylor then opened fire, the source said, and rushed out into the hallway to keep the youths from escaping as one of the suspects threw furniture at him.

Family members said yesterday that the shooting began after one of the youths got involved in an argument with Taylor, and that when a second youth tired to break up the argument, the shooting started.

Judy Thompson, a desk clerk at Landover House who was on duty Saturday afternoon, said that no one came to the lobby desk asking to visit Taylor. Visitors are told by a prominent sign in the lobby that they must check in with the front desk before entering, but strangers could have entered when the desk clerk was busy, Thompson said. There is also an unlocked rear entrance near the building's loading docks.