The city of Los Angeles put up $1 million in reward money Sunday for help catching Christopher Dorner, the renegade ex-cop accused of killing three people in a vendetta against his old department.

"We will not tolerate anyone undermining the security, the tranquility of our neighborhoods and our communities," Los Angeles Mayor Antonio Villaraigosa told reporters. "We will not tolerate this reign of terror that has robbed us of the peace of mind that residents of Southern California deserve. We will not tolerate this murderer remaining at large."

The offer -- raised in conjunction with businesses, private donors and community groups -- is "the largest ever offered to our knowledge," Los Angeles Police Chief Charlie Beck said. The hope is it will shake loose a tip that leads to Dorner's eventual conviction.

The Los Angeles Police Department says Dorner, a 270-pound, 6-foot former Navy officer, was fired in 2009 for filing a false complaint of excessive force against his training officer. In an interview aired Sunday on CNN affiliate KCBS, Beck called Dorner a "trained assassin" but said he wouldn't be harmed if he gave himself up.

"If you turn yourself in, then you will be safe and nobody else has to die," he said. "If you don't, if you decide to try to take the life of another Los Angeles police officer or their family member, then you'll have to suffer the consequences."

Amid the manhunt, the LAPD beefed up security at Sunday night's Grammy Awards show "out of an abundance of caution," police Cmdr. Andy Smith said. And Villaraigosa said authorities are confident they'll catch Dorner.

"This search is not a matter of if. It's a matter of when," Villaraigosa said. "And I want Christopher Dorner to know that."

Chief calls it 'domestic terrorism'

Dorner accused his training officer of kicking a mentally ill man during an arrest in 2007. The LAPD ruled the complaint unfounded and kicked Dorner off the force for filing a false complaint. He challenged his firing in court and lost.

In a manifesto released last week, he blamed racism and corruption in the department for his removal and vowed to wage "unconventional and asymmetrical warfare" against LAPD officers and their families. He called it a "last resort" to clear his name and strike back at a department he says mistreated him.

Beck had a different term for it Sunday.

"This is an act -- and make no mistake about it -- of domestic terrorism," he said. "This is a man who has targeted those that we entrust to protect the public. His actions cannot go unanswered."

But the chief announced Saturday that the LAPD would re-examine its proceedings against Dorner. The review is "not to appease a murderer," but "to reassure the public that their police department is transparent and fair in all things we do," he said.

"I am aware of the ghosts of the LAPD's past, and one of my biggest concerns is that they will be resurrected by Dorner's allegations of racism within the department," Beck said.

Mountain dragnet scaled back

Meanwhile, about 90 miles east of the city, the dragnet was back in action around the Big Bear Lake resort in the San Bernardino Mountains. After working through a weekend of heavy snow and overnight temperatures in the single digits, investigators were trying to pick up Dorner's trail anew after his burned-out truck was found there Thursday afternoon near the property of someone a federal arrest affidavit described as a known associate.

But there has been speculation, based in part on the affidavit, that the suspect could have crossed sate lines into Nevada or made his way into Mexico.

The day's effort began with about 60 officers, San Bernardino County sheriff's spokeswoman Lehua Pahia said. But by early afternoon, it had been scaled back to about 25 investigators, aided by a helicopter equipped with body-heat sensors and other specialized equipment, Pahia said. None of the tips the department had received so far has panned out, she said.

According to authorities, Dorner began making good on his threats a week ago when he killed Monica Quan and her fiance, Keith Lawrence, in a parking lot in Irvine, south of Los Angeles. Quan was the daughter of a now-retired Los Angeles police officer who represented Dorner in a disciplinary hearing that led to his termination.

Days later, early Thursday morning, Dorner allegedly opened fire on two LAPD police officers, wounding one, in the suburban city of Corona.