The night crew at Town Hall Liquors in College Park was delighted when the tall celebrity customer strolled in shortly before closing time. Everybody was glad to see Len Bias, the smooth and stylish basketball star who had just been drafted by the NBA champion Boston Celtics.

Clerks Marie Mulhare and Amy Masterman offered their excited congratulations, and night manager Mike Cogburn, a newly proclaimed Celtics fan, did something he had always thought silly. He asked for Bias' autograph.

On the back of a store receipt, Bias wrote his name in big sprawling letters. He started to hand the slip of paper to Cogburn, then remembered something else: "Hey, wait a minute, I found out my Celtics number today." Beneath his name, he added, "30."

It was 1:30 a.m. on Thursday, June 19. No one could know it was the last night of Len Bias' life. Everybody thought it was only the beginning for the gifted, 22-year-old athlete.

Five hours later, Bias collapsed in his dormitory suite at the University of Maryland in the presence of at least three other people. Last week, Maryland's chief medical examiner said that Bias died of "cocaine intoxication" after ingesting an unusually strong dose of the drug that stopped his heart within minutes. Friends who regarded Bias as a born-again Christian and a clean-living athlete who would never jeopardize his basketball career with drugs find the manner of death hard to reconcile.

For now, the story of Len Bias' final hours is filled with questions. What was Bias doing between 3 and 6:30 a.m.? Where did he get the fatal drug, described by a state drug official as "dealer quality" cocaine with far fewer impurities than cocaine sold on the street? Had Bias used the drug before? And what happened during those critical moments after his collapse?

Accounts of portions of the night are murky and sometimes contradictory. Rumors are rampant. Police have received and largely rejected reports of mystery women who claim to have spent part of the night in Bias' company.

Prince George's County State's Attorney Arthur A. Marshall Jr. announced last week that a county grand jury is investigating the events of the night, as well as possible illegal drug use by other University of Maryland athletes.

Sources have said that David Gregg and Terry Long, teammates and dorm mates of Bias, and Brian Tribble, a friend and former Maryland student, were with the star forward when he died. So far, the three have not discussed the case with police investigators and have said little to reporters.

Regardless of the details, the awful irony of Bias' death is undeniable. The comment by Celtic superstar Larry Bird -- "It's the cruelest thing I've ever heard" -- has become a catch phrase of the tragedy.

But earlier on this clear, comfortably cool night -- at the Bias family home in Landover, at Washington Hall dormitory, at Town Hall Liquors, wherever else Len Bias may have gone -- the eventual outcome was unthinkable.

The Town Hall staff said that Bias actually made two trips into the Rte. 1 lounge and store that serves a largely collegiate crowd. On the first visit, at about 1:15 a.m., he bought two six-packs of Private Stock malt liquor. On the second trip, about 15 minutes later, he bought a fifth of Hennessy cognac. Later, campus police would find empty Hennessy and Private Stock bottles in a dumpster behind Washington Hall.

Cogburn, 25, said that Bias dropped in perhaps once a week during the off-season to buy beer. On this night, he was wearing a Reebok cap, a memento of an endorsement deal he was making with the sporting goods line, a blue shirt with a gold chain necklace, and what friends describe as his signature piece of jewelry -- a gold identification bracelet with "Len" spelled out in diamonds. He was confident, smiling, well groomed as always. "He smelled sooo good," Mulhare said.

"Usually," said Cogburn, "he pretty much kept to himself. But you could tell he was real happy, real excited, enjoying life. I always like to cut up with customers and this time, I didn't feel like I was imposing on him."

Cogburn recalls their conversation when Bias returned to buy the cognac. First, Bias requested a pint of Hennessy.

Cogburn: "You're big money now. You need a fifth."

Bias: "Yeah, how much is it?"

Cogburn: "You don't really need to know, do you?"'

Bias, with a laugh: "Nah, I guess I don't." He paid for the $17 bottle with two tens.

Cogburn said he and Bias talked about the Celtics for a few minutes, Bias wrote the autograph, then Cogburn asked Bias how he was spending the evening.

"I'm out celebrating with my boy," is the reply both Cogburn and Mulhare remember.

Cogburn's final words to Bias were his usual send-off to customers. "Take care, Len," he said.

"You bet," Bias replied as he walked out the door. Home From Boston The evening had begun at 10 p.m. Wednesday, June 18, when New York Air Flight 67 from Boston landed at National Airport, bringing home Bias, his father James, and his agent, Lee Fentress of Advantage International.

The previous two days had been exhilarating and exhausting. The Celtics had made the 22-year-old Bias their first choice and the second pick overall in the National Basketball Association draft. Bias had made a commitment with Reebok to sign a long-term, six-figure-a-year contract that alone would have provided him with lifetime financial security, Fentress said. There had been a whirlwind of meetings, parties and interviews.

On Tuesday after the draft, Bias remarked to a reporter, "I'm tired. I just want to go home and see my mother." Bias had often told teammates that his first major purchase once the big money started rolling in would be a maroon Mercedes for "my mom."

But Bias would not see his mother again. In an interview with WRC-TV, Channel 4 News, Lonise Bias said she had spoken to her son by telephone while he was in Boston but got home late Wednesday night and missed seeing him when he dropped his father off.

Len Bias, driving his leased silvery-blue Nissan 300ZX, left his parents' house about 11:30 p.m., said his sister, Michelle Bias. County police say he went directly to the dormitory suite he shared with five teammates.

The suite is on the first floor of Washington Hall, a newly renovated red-brick building with white columns and white trim. It includes four bedrooms -- two singles and two doubles -- plus a living room and two bathrooms. The living room, where rescue attendants would work in vain to revive Bias, is furnished with brown couches and chairs and a small brown refrigerator with a portable ironing board on top. Before Bias' death, a life-size poster of the Maryland star in his basketball uniform covered one wall.

Keeta Covington, a defensive back on the Maryland football team, said he was in the dorm suite when Bias arrived. Covington said he ate crabs and discussed the Celtics with Bias, Long and Gregg, along with Keith Gatlin and Jeff Baxter, basketball players who also shared the suite. Another suite mate, freshman Phil Nevin, said he was visiting friends in Greenbelt until 2 a.m.; he returned to the dorm without seeing anyone and went to bed, he said.

Covington placed Bias' departure from Washington Hall at around 2 a.m., but Major James A. Ross, head of criminal investigations for the county police, says investigators are certain that Bias left the dorm shortly after midnight. Ross said he was seen getting into the Nissan with an unidentified woman.

Keith Gatlin, the Maryland point guard who was one of Bias' best friends, said he last saw Bias sometime before midnight when Gatlin turned in for the night.

"I told him I guess I had to be a Celtics fan now," Gatlin said.

"The last time I saw Lenny, he was sitting up on his bed, smiling and laughing," Gatlin said. "He was talking about going to rookie camp and playing one-on-one with Larry Bird. He was the happiest guy in the world." Whereabouts Uncertain

Where did Bias go when he left the dormitory?

One possibility that police are investigating is that he visited the nearby apartment of his friend, Brian Lee Tribble, a one-time Maryland junior varsity player.

Tribble, 24, lives at Seven Springs Village, a high-rise complex on Cherry Hill Road, less than three miles from the dormitory. The owner of a silvery Mercedes-Benz 450SL, Tribble has listed himself as president of Interior Services Inc. of 3010 Vista St. NE, which is his parents' home. D.C. corporate records have no record of such a firm.

Tribble and Bias were seen frequently at a dancing club called Chapter III in Southwest Washington. Other friends of Bias described the two as "social" friends who liked to go to nightspots together.

Tribble's two-bedroom apartment is furnished with a rust-colored corduroy couch and chairs, tables of blond wood and glass, a color television set with remote controls and a stereo with equalizer and 2 1/2-foot speakers. The monthly rent for two-bedroom apartments at the complex ranges from $649 to $699.

A man who identified himself as a friend staying at Tribble's apartment told reporters that Bias stopped by about 12:45 a.m. Also present, the man said, were Tribble and his roommate, Mark Fobbs, and an unidentified woman. The man said the group chatted for about 20 minutes, then Tribble and Bias left with the woman, saying they were going to drive her home. Police later identified the man as Ron Thomas. Visit to Liquor Store

The next time Bias' whereabouts can be pinpointed is at Town Hall Liquors, the tan-and-brown store a scant mile from the dormitory, in an area of Rte. 1 between Tribble's apartment and Washington Hall.

Cogburn, the night manager, said that he deliberately went to the door to watch Bias drive off after he bought the cognac "because I like his car." Another man, whom Cogburn said he could not identify, was sitting in the passenger seat, Cogburn said. The car turned left on Rte. 1, in the direction of the campus.

What happened next is uncertain. Sources familiar with the investigation said police had initially received statements indicating that Bias and Tribble might have driven into the District, to an area near Montana and New York avenues NE that D.C. police describe as a drug trafficking spot. But police say they now doubt that this happened. Said Ross, "How could he Bias have been in D.C. if he was in his dorm room?"

Maryland student Michelle Carpenter, a friend of Bias and his teammates, talked on the telephone with some of the dorm mates between 1 and 2 a.m., her roommate said. At one point, the roommate said, Bias got on the phone to say hello and accept congratulations from both Carpenter and the roommate, but the exact time is unclear. Jeff Baxter, Bias' roommate, said he last saw Bias in the suite between 2 and 3 a.m., when Baxter was preparing to go to bed.

In reports immediately after Bias' death, David Driggers, a friend with whom Bias often played in pickup basketball games, was quoted as saying that he saw Bias at Tribble's apartment as late as 2:30. Last week, however, Driggers told a reporter that he did not see Bias that night.

Police have taken statements from at least two women who claim to have been with Bias a few hours before his death. In an interview Monday, 24-year-old District resident Christine Johnson told The Washington Post she had met and talked with Bias near the campus between 4 a.m. and 5 a.m. She repeated her account in interviews on two Washington television stations. But police, after several interviews with Johnson, discounted her story.

A 40-year-old District woman also contacted county police last week, saying that Bias had visited her before his death and that she had given him $310 in cash, but again, police dismissed her version of events.

Ross said police believe that Bias was in his Washington Hall suite between 3 a.m. and 6:36 a.m., when county ambulance attendants arrived. What took place there is unclear.

The three men believed to have been with Bias in his final hours have shed little light on what happened. Less than two hours after Bias died, Maryland Coach Lefty Driesell summoned his players to his home and instructed them "what should be publicized and what shouldn't be publicized," player Nevin said.

"None of us are going to talk," said Terry Long, 21, the burly center who was administering cardiopulmonary resuscitation to Bias when paramedics arrived in the suite. "We haven't talked. We can't talk. It will all come out in the grand jury." Ambulance Is Called

What is known is that a man who identified himself as "Mr. Tribble" called the emergency assistance number, 911, at 6:32 a.m., requesting that an ambulance be sent to Suite 1103, Washington Hall.

When paramedics arrived, Bias, clad in a royal blue Reebok shirt, gray jeans and white high-topped sneakers, was lying on his back on the floor in Long's room between a bed and a desk. One attendant recalls seeing Keith Gatlin standing in a corner of the room, his eyes wide, his hand over his mouth.

Nevin said his dorm mates told him that Bias had suddenly leaned back on the bed in Long's room, saying he was tired and felt "terrible." According to a rescue attendant, others in the room said Bias "fell to the floor." Some described a "shudder," others a "seizure." At Leland Memorial Hospital in Riverdale, doctors worked until 8:50 a.m. before pronouncing Bias dead of cardiac arrest.

One evening last week, John Johnson, a freshman basketball player who had looked up to the older Bias, paused in the courtyard behind Washington Hall to remember his friend. Johnson had gone to bed early in his room at a nearby dorm that night and did not learn of the tragedy until the next morning.

"He could look at you and make you laugh," Johnson said. "And he had such style -- Giorgio Armani suits . . . . No less than the best for Len. He figured you only live once . . . .

"I want to know what happened to him," he said, "because let me tell you how I felt about the guy. When we were outside the hospital, waiting to hear how he was, I prayed to God to take me instead. That's how much I loved him."

Staff writers Keith Harriston and Sally Jenkins contributed to this report.