Police investigating the death of University of Maryland basketball star Len Bias found a clear plastic bag containing a white, powdery substance yesterday in his sports car and are conducting tests to identify it, law enforcement officials said.

Investigators are also trying to determine whether the 22-year-old all-America player and a friend drove early Thursday to an area in the District of Columbia where police say drugs are often sold.

Bias, one of the finest college basketball players in the country and a hero in the tiny Landover community where he grew up, was pronounced dead at 8:50 a.m. Thursday at Leland Memorial Hospital in nearby Riverdale.

He died of cardiac arrest. Sources close to the investigation said that cocaine was found in Bias' urine samples taken at the hospital. Sources said yesterday that drugs could have been a contributing factor in Bias' death.

Maj. James Ross, head of the Prince George's County police Criminal Investigations Division, said Bias' death "is being treated as a suspicious death and a criminal investigation is being conducted."

He said police will make no further comment until the state medical examiner's report is received.

Bias was the second player chosen in the National Basketball Association draft Tuesday and was the first player chosen by the NBA champion Boston Celtics.

By late yesterday, as Bias' family and friends continued to grieve, police said they had questioned two of Bias' dorm mates, Keith Gatlin and Jeff Baxter, also university basketball players, who had been in the campus dormitory suite when he collapsed about 6:30 a.m. Thursday.

Police were also trying to question three other men. Two of them are dorm mates and teammates Terry Long and David Gregg, and the third is Brian Tribble, identified as a longtime friend of Bias. Gatlin said that all three were present when he woke up and saw Bias unconscious in Long's room of the suite.

A fifth dorm mate, Phil Nevin, who has said he was sleeping when Bias collapsed, will be interviewed as part of the routine investigation. All six dorm mates were enrolled in summer school.

Long was trying to revive Bias when paramedics arrived. Bias, clad in blue jeans and a Reebok T-shirt, had collapsed in Long's room and was lying unconscious and limp on the floor, according to one member of the rescue squad.

Gatlin and Baxter said they were asleep when Bias became ill and woke up when paramedics arrived. Police said yesterday they had no reason to doubt the accounts of Gatlin and Baxter.

Maryland's chief medical examiner, Dr. John Smialek, released no new details yesterday on the results of tests being conducted to determine the cause of death. Officials in the Baltimore office said it could be more than a week before complete autopsy reports are available.

A memorial service will be held at 7:30 p.m. Monday on the basketball court in the university's Cole Field House, where Bias became the school's all-time leading scorer. The 6-foot-8-inch forward was twice named the Atlantic Coast Conference player of the year, and he averaged 23.2 points a game in his senior year.

Yesterday afternoon, as police continued their investigation, a man who identified himself as John Williams answered the door at an apartment on Cherry Hill Road near the campus in College Park where several friends said Tribble lived.

Williams, who said he had been interviewed by police and was staying with Tribble for a few days, described Tribble as a friend of Bias' from college who now works for an upholstery and rug cleaning business in the District.

Williams, who said he was home from college, said he had been at Tribble's apartment when Bias stopped by about 12:45 a.m. Thursday, some hours after returning from Boston, where he and his father James had met with Celtics officials.

Also present, he said, were Tribble and his roommate, Mark Fobbs, and a woman whose name Williams said he did not know. The group had been chatting for about 20 minutes, according to Williams, when Bias suggested to Tribble that they "go party."

Williams said Tribble, Bias and the woman left in Bias' leased car and that the two men said they were going to drive the woman home.

Accounts of what happened in the next few hours vary. Sources familiar with the investigation said police have received statements indicating that Bias and Tribble went to the District near Montana and New York avenues NE. D.C. police spokesman Lt. William White III characterized the location as well known as a drug trafficking area and said there had been several arrests there in recent days on heroin, cocaine and PCP charges.

"The area . . . is known for its on-the-street drug sales," he said.

A number of Maryland players were interviewed informally yesterday by Maryland Coach Lefty Driesell in his Cole Field House office. Driesell has been given a report on the police investigation, according to sources.

Athletic Director Dick Dull confirmed that Driesell met with two Prince George's police detectives Thursday night.

Among those who visited Driesell yesterday was Long, who said that he had not spoken with county detectives and that he had contacted a lawyer.

Asked to review the details of Bias' death, Long said, "I'm still upset. I don't want to discuss it. I discussed things with my lawyer. You'll have to talk to him."

Boston Celtics President Red Auerbach confirmed yesterday that he and Driesell had talked after Bias' death and that Driesell had acknowledged that drugs might have been involved.

According to Auerbach, Driesell said to him: "Red, there's some sort of an indication that there might be some drug involvement or something like that on a one-time basis . . . . But if it was, it was undoubtedly a first-time experiment. He was so happy, you know. Somebody must have talked him into something."

Police have been in contact with an attorney for Tribble, said Prince George's County Officer Carol Landrum. She said his attorney would not bring Tribble in for an interview with detectives.

Alan J. Goldstein, a lawyer who is representing Long and Gregg, said late last night that neither player had talked with county police about the hours before Bias' death. Goldstein would not say whether Long and Gregg would talk to homicide investigators. He also refused to comment about whether he had talked with investigators or with Driesell.

Prince George's County Detective Michael Ferriter said police found no evidence of drugs when they searched the dormitory suite that Bias shared with basketball players Long, Gatlin, Gregg, Baxter and Nevin.

One member of the rescue crew said he saw no evidence of drugs or alcohol.

The emergency attendant, who asked not to be identified, described the room as a typical college dormitory, strewn with clothes but otherwise orderly. Bias "was in the bedroom on the floor. We dragged him into the living room," said the attendant.

He said Bias' eyes were open but he was not breathing and his heart had stopped beating by the time paramedics arrived. Technicians appplied cardiopulmonary resuscitation and eventually administered an electrocardiogram, which showed a "flat line," according to the attendant.

Nevin said his dorm mates told him that Bias leaned back on the bed in Long's room and said he was tired and felt "terrible." According to the attendant, others in the room said Bias "fell to the floor," with what some described as a "shudder" and others called a seizure. "His body was lax, there was no muscle tenseness. His eyes were open. They were dilated," said the attendant.

He said that "five or six" other men were in the suite with Bias and that "all were up and dressed."

Bias' parents, who had remained secluded at their home Thursday, made funeral arrangements yesterday and visited Driesell at his office but made no public statement about the circumstances of their son's death.

Among Bias' close friends and teammates, the mood remained somber as they talked about the death of a young man who only two days earlier seemed on the brink of a brilliant career as a professional basketball player.

Basketball player Tony Massenburg, who joined his teammates at the hospital emergency room after learning that Bias had collapsed, described the scene as their friend was pronounced dead.

"There were about 14 of us, and his mother came out and told us. We all cried uncontrollably," he said.

"I just thought he was sick. I kept thinking, 'Lenny will pull it out, he'll pull it out. He always pulls us out. So he'll pull it out for himself.' But he didn't."

Staff writers Keith Harriston, Victoria Churchville, Joseph Bouchard, John Ward Anderson, Tom Kenworthy, Ed Bruske and Alexandra Clough contributed to this report.