Lopez said two LAPD officers were in Corona on special detail to check on one of the individuals named in Dorner's manifesto and encountered Dorner. Dorner allegedly grazed one of them but missed the other.
"[This is an] extremely tense situation," Lopez said. "We call this a manhunt. We approach it cautiously because of the propensity of what has already happened."
After Dorner allegedly shot at LAPD officers in Corona, he fled and encountered two Riverside police officers stopped at a red light in their police car. Dorner used a rifle to shoot through their windshield, killing one officer and injuring the other, police said.
The deceased officer was a 34-year-old, 11-year veteran of the police department. The injured officer, age 27, was expected to make a full recovery.
Diaz said that the names of the officers were being withheld to protect their families, who might be targeted by Dorner if the names were released.
"They were on routine patrol stopped at a stop light when they were ambushed," Lt. Guy Toussant of the Riverside Police Department said.
In the manifesto Dorner published online, he threatened at least 12 people by name, along with their families.
"Your lack of ethics and conspiring to wrong a just individual are over. Suppressing the truth will leave to deadly consequences for you and your family," Dorner wrote in his manifesto.
A badge and identification belonging to Dorner have been found in San Diego, according to San Diego Police Sgt. Ray Battrick. Dorner's LAPD badge and ID were found by someone near the city's airport and turned in to police overnight, The Associated Press reported.
Los Angeles Police Department Chief Charlie Beck said today that 40 protective details have been deployed to protect officers and their families.
"We are taking all measures possible to ensure safety of our officers and their families," he said.
Dorner is also believed to be responsible for the weekend slayings of an assistant women's college basketball coach, Monica Quan, and her fiance, Keith Lawrence, in what cops believe were acts of revenge against the LAPD, as suggested in his online manifesto.
Lawrence was found slumped behind the wheel of his white Kia in the parking lot of their upscale apartment complex in Irvine, Calif., Sunday and Quan was in the passenger seat.
"A particular interest at this point in the investigation is a multi-page manifesto in which the suspect has implicated himself in the slayings," Maggard said.
Police said Dorner's manifesto included threats against members of the LAPD, and so the department is taking extra measures to ensure the safety of officers and their families.
The document, allegedly posted on an Internet message board this week, apparently blames Quan's father, retired LAPD Capt. Randy Quan, for his firing from the department.
One passage from the manifesto read, "I will bring unconventional and asymmetrical warfare to those in LAPD uniform whether on or off duty."
"I never had the opportunity to have a family of my own," it read. "I'm terminating yours."
Dorner was with the department from 2005 until 2008, when he was fired for making false statements.
Randy Quan, who became a lawyer in retirement, represented Dorner in front of the Board of Rights, a tribunal that ruled against Dorner at the time of his dismissal, LAPD Capt. William Hayes told The Associated Press Wednesday night.