Prince George's State's Attorney Arthur Marshall Jr. said yesterday that Terry Long and David Gregg, two teammates who were with former University of Maryland basketball star Len Bias on the morning that Bias died, might be offered immunity from prosecution in exchange for their testimony before a county grand jury.

At a news conference yesterday formally announcing the grand jury investigation into Bias' death, Marshall said the 22-year-old all-America player might have collapsed in his Washington Hall dormitory suite 15 to 30 minutes before an ambulance was called at 6:32 a.m. last Thursday. Marshall said the grand jury will begin its investigation next week.

Marshall said that cocaine was involved in Bias' death, but that the exact cause of the death could not be determined until the state medical examiner's autopsy report is issued this week.

Evidence of cocaine was found in a urine sample taken from Bias at Leland Memorial Hospital in Riverdale after he was pronounced dead of cardiac arrest at 8:50 a.m. Thursday, police sources said. A plastic bag containing what police said was cocaine was found in Bias' leased Datsun 300ZX and Marshall said yesterday that drug paraphernalia -- including cut straws containing cocaine crystals -- beer bottles and a cognac bottle were found in a dumpster outside the dormitory.

"Based on all of the information we have, cocaine was involved in the death of Len Bias," Marshall said. "Who brought the drugs into the car and the dorm and where the drugs came from are questions we don't have answers for."

Without elaborating, Marshall said, "It appears that Long and Gregg didn't bring drugs into the room." Brian Tribble, a friend and former junior varsity player at Maryland, was in the dorm room with Long and Gregg when Bias collapsed, according to sources close to the investigation.

Police have sought unsuccessfully to question Long, Gregg and Tribble.

Marshall said that when investigators searched the dormitory suite shared by Long, Gregg, and players Keith Gatlin, Jeff Baxter and Phil Nevin, "the room was spotless."

"I've never been in a college room where there wasn't one bottle of beer," Marshall said. "Even the paramedics' materials were cleaned up. Sanitized. That's a good word for it."

The role played by the university's men's basketball coach, Lefty Driesell, in the aftermath of Bias' death will also receive close scrutiny by the grand jury, Marshall said. Driesell, according to Marshall, summoned team members to his house "almost immediately" after Bias died and instructed them not to comment on certain aspects of the case.

"I don't know whether it's proper for a coach to tell his players what to say and what not to say," Marshall said. "I don't think it's right that he took them away from the hospital so quickly. That's something I would like to ask him about."

In addition, Marshall said, the university "has not been as candid, just as it hasn't been in the past. A little self-examination may be called for."

Driesell likely will be subpoenaed for grand jury testimony, Marshall said.

Driesell, who spoke at Bias' funeral service last night, said, "I have no response. Today is the day we're honoring Len Bias."

Marshall said he met yesterday with the attorney representing Long and Gregg, Alan Goldstein, who raised the idea of immunity for his clients if they agreed to testify before the grand jury.

The immunity would amount to an agreement that Marshall's office would not prosecute the witnesses based on their testimony, Marshall said. The witnesses would be held in contempt of court, and possibly jailed, if they failed to testify in open court against persons charged with crimes as a result of the grand jury investigation, Marshall said.

Possible criminal charges could include possession and distribution of cocaine, Marshall said. But the investigation could lead to a manslaughter charge against any person who supplied Bias with drugs, he said, if the state medical examiner's autopsy report concludes drugs contributed to Bias' death.

Marshall said about 12 people who were with Bias between 11:30 p.m. Wednesday and 6:30 a.m. Thursday might be subpoenaed to testify before the grand jury.

Dr. John Smialek, the state's chief medical examiner, said yesterday that autopsy results are expected today or early tomorrow. Smialek said his office was trying to find out whether drugs were a factor in Bias' death. He said a final determination would be possible when a toxicology report and a microscopic examination of tissue samples from Bias' heart and other vital organs are completed.

Although Marshall said Bias may have collapsed between 15 and 30 minutes before the ambulance was called to his dorm suite, one member of the emergency crew that tried to revive him said it appeared he had collapsed about 10 to 15 minutes before paramedics arrived. He said he based that on Bias' body temperature.

Medical studies show that chances of survival are greatly increased if cardiopulmonary resuscitation begins within three to five minutes after a person's heart stops beating.

Staff writer Susan Schmidt contributed to this report.