A $1 million check written by Hustler magazine publisher Larry Flynt, purportedly for the contract murders of singer Frank Sinatra and three publishers, was really just a practical joke, Flynt's lawyer says.

"The allegations are totally unfounded," Flynt's attorney, Alan Isaacman, said Thursday. "Back in November 1983 Larry Flynt had a dinner party and gave out, as a joke, million-dollar checks to about half a dozen people."But Los Angeles County Sheriff Sherman Block said he was taking the matter seriously.

"I've been led to believe that Larry Flynt has a propensity to try to harm people he sees as his enemies, whether (over) business arrangements or whatever," Block said Wednesday.

No charges have been filed. Sheriff's Capt. Robert Grimm said an investigation is continuing.

Authorities allege Flynt wrote the check on Nov. 14, 1983 to Mitchel L. WerBell for the slaying of Sinatra, Playboy Publisher Hugh M. Hefner, Penthouse Publisher Robert Guccione, and former TV Guide publisher and U.S. ambassador Walter Annenberg.

"I think he was just a little crazy," said Guccione, who added he does take the threat seriously. "It was a very irrational act because neither Hefner nor I compete with his magazine . . . And if you factor in Annenberg and Sinatra, it becomes even more irrational. For me, I just put it down to Flynt's obvious dislike for me."

Said Hefner: "When you're a celebrity and controversial, you wind up on one of those crazy lists with Reagan, Sinatra and the pope."

Sinatra's publicist, Susan Reynolds, said the entertainer had no comment.