Inquiry of Coastal Commissioner Widens : Grand jury: Investigators are looking into allegations that Mark Nathanson extorted payments for votes. Files on more celebrities’ homes have been subpoenaed.

A federal grand jury has stepped up its criminal investigation of California Coastal Commissioner Mark L. Nathanson in the past month, subpoenaing commission files on more than a dozen houses, including the Malibu homes of such Hollywood figures as actress Sharon Gless and “Rocky” producer Irwin Winkler, The Times has learned.

Nathanson has been under investigation for allegedly using his influential office to extort payments from applicants seeking building permits from the coastal panel, set up to safeguard the state’s 1,100-mile coastline.

The Times previously reported that federal agents were looking into allegations that Nathanson, a Beverly Hills real estate broker, had attempted to extort payments from actor Sylvester Stallone, former Fox Inc. Chairman Barry Diller and producer-agent Sandy Gallin. In March, the grand jury obtained permit records for Malibu homes owned by all three, according to subpoenas served on the Coastal Commission.

Sources familiar with the investigation say that the grand jury activity since the beginning of March has accelerated with a flurry of subpoenas aimed at wrapping up the inquiry of Nathanson, 52, begun more than 18 months ago.

In general, federal authorities have viewed those who have gone along with demands for payments as victims and not as criminals.

But many of those whose records were subpoenaed refused to return reporters’ phone calls. Others declined to comment or said they were puzzled at the grand jury’s interest in their property, maintaining that they had no contact with Nathanson. Others acknowledged having testified before the grand jury. With the exception of a Gless spokeswoman, none would talk for quotation.

Nathanson’s attorney, Robert L. Shapiro, said: “I assume the government is doing a very thorough investigation, which we believe will clear Mark Nathanson of receiving any illegal payments in connection with his appointment as a coastal commissioner.”

Nathanson has not been charged with any crimes and Assembly Speaker Willie Brown (D-San Francisco), who appointed him, has stood by the commissioner.

Last year, former Sen. Alan Robbins implicated Nathanson in an elaborate scheme to split $250,000 extorted from San Diego hotel developer Jack Naiman, who initially sought to block a rival hotel from being built along the La Jolla coastline. After resigning from office, Robbins pleaded guilty to charges of income tax evasion and racketeering and is awaiting sentencing.

With the cooperation of Robbins and others, the grand jury is investigating allegations about Nathanson’s conduct during six years on the Coastal Commission.

The grand jury has obtained commission permit files on homes owned by Disney studio chief Jeffrey Katzenberg, “Love Boat” producer Douglas Cramer and Warner Bros. Films executive Terry Semel, as well as Gless and Winkler.

Subpoenas also were issued for permit files of three Southern California businessmen, according to sources familiar with the investigation.

In many cases, it is unclear whether Nathanson played any part in the permit application or what wrongdoing the grand jury might be investigating.

In one case, Nathanson did play a public role, intervening to reverse a commission vote that affected Winkler’s remodeling, records show.

Winkler--the Oscar-winning co-producer of such movies as “Rocky” and “Raging Bull”--sought in 1988 to remodel his oceanfront Malibu house. But he could not move ahead with plans to add a second story and remodel a teahouse without commission approval.

In July, 1988, the commission’s staff recommended that Winkler’s permit be approved, but with restrictions, records show. If Winkler wanted to expand his house, he would need to persuade county health officials that the home’s antiquated septic tank system could protect the beach from contamination by raw sewage. Without updating the house’s plumbing, he should get no coastal permit, the staff said.

When the full, 12-member Coastal Commission took up the proposal, it first agreed with the staff recommendations, but at the same meeting reversed itself.

In a handwritten note inserted into the transcript of the commission’s July 12, 1988, meeting, Coastal Commission Director Peter Douglas marked the precise moment in the debate when the commissioners made the turnaround.

“This is apparently when Commissioner Nathanson said something to Commissioner (Donald) McGinnis, because the next vote appears to reverse the vote just taken,” Douglas said in the December, 1991, memo.

Two sources familiar with Winkler’s Malibu permit said they were recently questioned by the FBI about any financial transactions regarding the application to remodel the producer’s oceanfront Malibu house.

“I was asked if money was paid to Nathanson,” said one of the sources, who asked not to be identified. Neither source said they knew of any payments to Nathanson.

Winkler refused to talk to Times reporters.

In some cases it is unclear what the grand jury, which conducts its sessions in secret, is investigating. Federal authorities have refused to comment on the grand jury proceedings.

Gless--through a spokeswoman--said federal authorities have not contacted her. But Gless acknowledged meeting Nathanson about two years ago at a dinner party and talking about plans for deck work at her Malibu home, according to her spokeswoman, Heidi Schaeffer.

In the course of dinner conversation, Gless, star of television’s “The Trials of Rosie O’Neill,” learned that Nathanson was a member of the commission and she asked him how to go about filing an application for the work, Schaeffer said. Nathanson referred Gless to an assistant at a law firm, which she later retained, Schaeffer said.

“That was the first and last she ever heard from Nathanson,” Schaeffer said. Gless was granted a permit for deck improvements, which were rejected by a local homeowners association.

Sherman Stacey, Gless’ lawyer, said he remembered the project as “fairly routine from a Coastal Commission point of view.” He said he has no knowledge of any connection between the project approval and Nathanson. “Gless never mentioned to me she ever even met him,” Stacey said.

In another case, the grand jury subpoenaed records on a Malibu home owned by songwriters Carol Bayer Sager and Burt Bacharach, but the connection to Nathanson is unclear. The commission said it could find no permit for the couple on file. Sager and Bacharach could not be reached for comment, but a source close to the couple said they “didn’t apply or get a Coastal Commission permit” and there was “no information to indicate they had any contact” with Nathanson.

Although most of the subpoenas were for records of Hollywood celebrities or executives, the grand jury also obtained files for three other coastal property owners. They were for La Jolla property owned by hotelier Naiman, the Newport Beach home of businessman Bruce Nordlund, and a Malibu home owned by Barry Mendelson, whose father founded Nate ‘n Al’s restaurant in Beverly Hills.

It is not apparent why the grand jury obtained their files or those of Katzenberg, Semel and Cramer.

For two decades, Nathanson has bridged the world of Hollywood and politics. He has worn a variety of hats: appointed member of local government panels, real estate broker, remodeler of homes, campaign fund-raiser and consultant to Hollywood producers. Brown appointed Nathanson to the Coastal Commission in 1986.

Two years ago, Brown, using powers given him as a lawmaker, performed the ceremony at Nathanson’s wedding.

The marriage lasted only a few months, but the divorce proceedings, finalized last December, provide a glimpse into Nathanson’s finances. In a sworn statement filed last July in his divorce, Nathanson listed $6.6 million borrowed against his home and two other properties. He also reported $63,050 in monthly expenses but said he had no monthly income.

In another sworn statement, Nathanson said he had been trying to sell the properties but had been unsuccessful “due to the economic recession. . . . I have been forced to live off of funds loaned to me against the equity in these houses.”

As a member of the Coastal Commission, a part-time post, Nathanson receives $100 per meeting plus expenses.