The Los Angeles County Grand Jury has called for the district attorney to investigate long-term leases that the county granted to private developers on choice waterfront property in Marina del Rey, The Times has learned.

The grand jury wants Dist. Atty. Gil Garcetti to determine if any laws were broken or procedures ignored when the county renegotiated leases on valuable county-owned marina property in 1989, according to two members of the panel.

"The county was a loser in each one of these leases," said one grand juror, who asked not to be identified. "Was it ignorance, stupidity or duplicity?"

A spokeswoman for the district attorney said Garcetti had not received the grand jury's request and would have no comment. Grand jury adviser Terry White, a deputy district attorney, said he has not had time to prepare the formal referral to the district attorney but plans to do so in the near future. He added that the district attorney is not obligated to act on a grand jury referral.

The grand jury, which finished its term June 30, stated in its final report that it had conducted a preliminary investigation into the marina. Two grand jurors said the panel decided the leases warranted further examination and voted to refer the case to the district attorney in part because members felt they lacked the expertise to evaluate the complex agreements.

Most of Marina del Rey is owned by Los Angeles County, which leases it on a long-term, generally 60-year, basis to a small group of developers who operate the harbor's apartments, hotels, boat slips, restaurants and shops. The vast majority of the marina properties are controlled by a handful of developers, who also have been significant campaign contributors to the county Board of Supervisors.

A yearlong Times study of the marina published in April, 1992, found that the partnership between the county and the leaseholders had primarily benefited the developers at the expense of the public.

Independent real estate experts consulted by The Times concluded that the marina leases were generating far less rental income for the county than they should given the value of the prime waterfront property. The experts also said the county made a big financial concession to the leaseholders when new rent levels were negotiated in 1989.