Police said today that the sniper who shot civil rights leader Vernon Jordan lay in wait in tall grass overlooking Jordan's hotel room for at least 20 minutes and possibly an hour or more.

Deputy Police Chief Ernest Walters said the grassy area where a cartridge case was found was matted down too tightly for the assailant to have arrived just before Jordan did.

The calculation underscored what the FBI special agent in charge, Wayne David, described as the deliberate nature of the attack. He told reporters that he had no reason to disagree with the police estimate.

Walters said it was possible that Jordan's attacker had been hiding for less than 20 minutes on the grassy slope from which he fired, "but I doubt it."

"It was matted down pretty good," he said.

The FBI's Davis, however, cautioned against any conclusion about motives for the shooting. He frankly acknowledged that investigators are no closer to a solution than they were five days ago.

Now recuperating in a local hospital, the National Urban League president was shot in the back early last Thursday morning as he stepped out of a car less than 50 feet from his room at the Marriott Inn here.

Jordan's driver and companion that night, Martha C. Coleman, 36, was questioned by FBI agents for two hours yesterday and by Fort Wayne police for a little more than an hour this morning.

Agent Davis said "she was very cooperative, she wants to be helpful," but the FBI interview produced "nothing we did not already know."

Asked at a press conference today if Coleman had been ruled out as a possible accomplice, Davis said yes.

As for the course of the investigation, he still envisioned a long, painstaking one. The FBI had already interviewed about 350 individuals when Davis stopped counting a day or two ago, and the number increased markedly since then.

"The investigation is continuing," Davis said, in the classic police parlance, that means no end is in sight. But he refused to concede that it was stalled.

"We have a lot of leads," he said, "but we are no closer right now to who or why."

The FBI believes that the sniper fired a single shot at Jordan from a perch in the grass about 45 yards from where Coleman parked her car around 2 a.m.

Ballistics and other scientific tests, not yet complete, indicate that the copper-jacketed 30-06 bullet may have hit a chain-linked fence bordering the hotel's brightly lit parking lot before a fragment tore a hole in Jordan's back.

An even bigger lead fragment, slightly more than half the weight of a full-size bullet, was found on the pavement just outside Jordan's room, Davis said. Lab tests on that piece show no traces of human blood or protein, but he said these findings do not necessarily prove that it didn't hit Jordan.

Despite initial assertions by Mayor Winfield Moses Jr. that the gunman was "a professional" or at least an "expert" marksman, Davis said that "it's not a difficult shot." He added that none of the witnesses interviewed thus far reported hearing more than one shot.

What is striking about the gunman's vantage point, however, is that it commanded a clear view not only of the spot where Coleman parked her car but also of the door to Jordan's first-floor room.

The police estimate of how long the sniper had been waiting also appeared to rule out any possibility that the attack might have been carried out by the three white males in a dark-colored car who shouted some sort of insult either at the 44-year-old Jordan or at Coleman, who is white, as they drove to the hotel. That incident took place about a mile from the Marriott around 1:45 a.m., 20 minutes before the shooting.

Allen County sheriff's deputies today completed their search of a four-mile stretch of Interstate 69, which runs past the hotel, and came back with only a rain-soaked T-shirt to submit for laboratory tests.

"It's certainly nothing to pine high hopes on," Mayor Moses observed.

The interviews with Coleman ended a stalemate between law enforcement authorities and her chief lawyer, Charles F. Leonard. He had complained that he had been kept cooling his heels at police headquarters early Thursday while police conducted their first interrogation of his client elsewhere in the building.

Mayor Moses acknowledged today that police did not tell Coleman her lawyer was waiting outside, but he dismissed this as "not a major issue.

"Evidently there was some confusion as to whether he was her lawyer," the mayor said. Coleman had tried to secure a lawyer by telephone from the hotel lobby immediately after the shooting, but the individuals she called did not contact Leonard until 5 a.m.

By the time Leonard got down to the police station, the mayor said, Coleman had already been asked several times whether she wanted a lawyer present and she had signed a statement saying she did not.

It turned out today that the lawyer she first got on the phone was Assistant U.S. Attorney David H. Miller, a longtime friend who had been her attorney when he was in private practice.

"She said she didn't know where else to turn, or what to do," he said. "I told her I couldn't represent her. I asked her if she was involved and she said no, so I said, "Tell them what you know.'"

Miller said Coleman called him three times that morning, the third time from police headquarters after she had signed the statement saying she did not want a lawyer. But when Miller asked if she did, she said she didn't know. At that point, he said, he called Leonard.

Miller said he, too, went to police headquarters, intending to tell Coleman of the arrangements and then to drive her home after the questioning. But the attorneys never ran into each other. Miller said he also asked for Coleman, but "one of the officers said she wasn't there."