UPPER MARLBORO, Md. (AP) _ The parents of star Len Bias are among those waiting to testify before a grand jury investigating the cocaine-poisoning death of the Maryland basketball star.

As the Prince George's County grand jury moved into its fourth day of hearings today, there was no word on when James and Lonise Bias would testify or what they might say, their attorney, Wayne Curry, said.

''All they know is their son is dead, and there were other people involved and apparently narcotics involved,'' Curry said.

Curry said the Biases, who were not subpoenaed, decided to accept an offer made about two weeks ago by county prosecutor Arthur A. Marshall Jr.

The Biases have criticized statements by Marshall and the publicity surrounding their son's death.

Len Bias' ''name has been linked with entirely unrelated pursuits such as gambling, point shaving, things of that sort, which have cast him in a light that may not be conducive to zeal on the part of jurors,'' Curry said.

Witnesses called Wednesday included paramedics summoned to a dormitory room when Bias collapsed about 6 a.m. on June 19, and most of the people known to have been with him the day he died.

The grand jury heard testimony from Jeff Baxter and Keith Gatlin, two of Bias' roommates, and Christina Johnson, a women who saw the All-American that morning.

Jurors also heard from Johnnie Walker, a District of Columbia police officer and Bias friend who retrieved articles from his room at the request of Bias' parents.

Most witnesses refused to talk to reporters when they left the grand jury room, and those who did had little to say.

Among those not yet summoned are Terry Long and David Gregg, two fellow basketball players, and Brian Lee Tribble, who were in the dorm room when Bias collapsed.

Marshall has said he would wait until he had finished with other witnesses before deciding whether to subpoena Long and Gregg. Under Maryland law, anyone subpoenaed before a grand jury in a drug case is immune from prosecution on related charges.

Marshall said he does not plan to subpoena Tribble, the man he alleged was the source of the cocaine that killed Bias.

Marshall said last week that indictments could be returned as early as Friday for charges of use, possession and distribution of drugs.