A package, mailed to the McCallum Theatre, which contained a suspicious white powder forcing the evacuation and quarantine of the Palm Desert venue this afternoon was meant for HBO personality Bill Maher, officials have confirmed tonight.

Maher, a liberal political and social satirist, is scheduled to appear at the venue tomorrow night.

The package, which was opened by McCallum staff shorty after 11:30 a.m., was "addressed to Bill Maher," said Riverside County sheriff's Cpl. Matt Spain this evening.

"It contained specific threats made against Bill Maher," Spain added. He declined to go into specifics.

McCallum Theatre officials alerted authorities a short time after discovering suspicious white powder inside the package.

Authorities responded along with a hazardous materials team that evacuated those inside the venue that could be evacuated, and quarantined others who came into contact with the powder.

Herlinda Valenzuela, a spokeswoman with the sheriff's department, said four people inside the Palm Desert theater were "decontaminated."

The building,73-000 Fred Waring Drive, was shut down for more than five hours and tonight's concert featuring singer-guitarist Boz Scaggs was canceled.

Promoter Jim Fitzgerald said he has spoken with Scaggs and he wants to reschedule the concert, but said sheriff’s officials have told him not to comment because they plan to make an official statement about the situation.

But Fitzgerald said, “You can imagine how crazy it is.”

Sam Gershenfeld, wife of Mitch Gershenfeld, McCallum director of Presentations and Theater operations, said during the quarantine that she hadn’t been able to see her husband since 2 p.m.

She didn’t know why the theater had been quarantined or how many people inside the theater were affected.

She just heard a suspicious substance was sent to the theater.

MItch Gershenfeld, reached tonight, declined to discuss the ordeal, but said Maher's 8 p.m. appearance tomorrow would go on as scheduled.

Fitzgerald said 900 tickets had been sold to the Boz Scaggs concert.

Early testing indicates the powdery substance in the package was not harmful, FBI spokeswoman Laura Eimiller said.

The FBI Joint Terrorism Task Force is investigating the incident.