Big Bear Lake, California (CNN) -- The Los Angeles Police Department will reopen its investigation into the firing of an officer that prompted alleged revenge attacks as the hunt for the man accused of killing three people widened in Southern California's San Bernardino Mountains.
Christopher Jordan Dorner declared war on police in a manifesto after being fired by the LAPD and losing appeals to be reinstated, claiming that racism in the police department was behind him losing his job.
"I feel we need to publicly address Dorner's allegations regarding his termination," LAPD Chief Charlie Beck said in a statement released Saturday.
"...I do this not to appease a murderer. I do it to reassure the public that their police department is transparent and fair in all things we do."
Beck ordered a re-examination of all evidence and new interviews with all witnesses connected to Dorner's 2009 firing after the LAPD ruled that he lied two years earlier in a complaint he filed against his training officer.
"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.
In the manifesto posted online, 33-year-old Dorner promised to bring "unconventional and asymmetrical warfare" to officers and their families, calling it the "last resort" to clear his name and strike back at a department he says mistreated him.
According to authorities, Dorner began making good on his threats a week ago when he allegedly 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 resulted in his termination.
Days later, early Thursday morning, Dorner allegedly opened fire on two LAPD police officers, wounding one, in the suburban city of Corona.
Roughly 20 minutes later, Dorner allegedly fired on two police officers, killing one and wounding another, in the nearby city of Riverside.
Since then, much of the manhunt for Dorner has focused in and around the San Bernardino County mountaintop resort of Big Bear Lake after Dorner's pickup was found burning in the area.
As the dragnet entered its fourth day Sunday, the manhunt widened with the creation of a joint task force that brought together state and local law enforcement officials along with the FBI and the U.S. Marshals Service.
"We will look under every rock. We will look around every corner. We will search every mountaintop," Riverside Asst. Police Chief Chris Vicino told reporters Saturday.
In the snow-packed San Bernardino Mountains, officers trudged through fresh snow as they searched homes, knocking on doors and peeking in windows, for Dorner.
But as the search continued with no sign of Dorner, questions were raised about whether he escaped the dragnet -- possibly days earlier.
A federal arrest warrant affidavit said Dorner's burned-out truck was found on the property of a known associate in the Big Bear Lake area Thursday afternoon.
There has been no sign of Dorner since Thursday, and there has been speculation, based in part on the affidavit, that he has possibly crossed state lines into Nevada or made his way into Mexico.
Authorities say Dorner spent at least two days in the San Diego area following the shooting of Quan and her fiance.
Dorner's ID and some of his personal belongings were found Thursday at the San Ysidro Point of Entry at the U.S.-Mexico border, according to the affidavit.
Border patrol agents have been searching cars crossing into Mexico for signs of Dorner, while authorities have searched a home Dorner owned in Las Vegas and one owned by his mother in La Palma, California.
Two sailors also reported Dorner, a former Navy lieutenant, approached them at the San Diego-area Point Loma Naval Base, and local police allege he attempted to steal a boat.
Even so, the focus of the manhunt remains on the San Bernardino Mountains where the search has been slowed by heavy snowfall.
Search teams were aided by helicopters, snowcats and armored personnel carriers with snow chains.
Los Angeles-area police and a number of military installations have been on alert since the shootings, while authorities chase down a number of unconfirmed sightings of the 270-pound, 6-foot Dorner.
In the manifesto and on a Facebook page, Dorner allegedly singled out as targets a number of officers and their families, who have been under guard since the shootings.
The LAPD chief on Saturday described the police shooting of two women who were driving a pickup similar to the one Dorner owned as a "tragic, horrific incident."
In an interview with CNN affiliate KCBS, Beck said the shootings of Margie Carranza, 47, and her mother, 71-year-old Emma Hernandez, occurred a day after the manhunt for Dorner began.
He said the officers were under enormous pressure.
CNN's AnneClaire Stapleton and Irving Last contributed to this report. Paul Vercammen and Stan Wilson reported from Big Bear Lake. Chelsea J. Carter wrote from Atlanta.