Possible Cop Killer Dorner in shoot out in Big Bear

[Posted at 4:31 p.m. ET] Law enforcement officers are responding to reports that ex-LAPD officer Christopher Jordan Dorner has been sighted and may have been involved in a robbery in the Big Bear area of southern California, said law enforcement sources involved in the investigation.
Dorner – who indicated he was on a campaign of vigilante justice for what he believes was his unfair termination from the LAPD in 2008 – has been the subject of a seven-day manhunt as a suspect in three killings.
Dorner is accused of killing one police officer and wounding two others, as well as killing the daughter of his police union representative and her fiancé.

[Updated at 4:35 p.m. ET] The San Bernardino Sheriff's Department confirms that authorities were chasing a pickup truck, according to CNN's Casey Wians. The department hasn't confirmed whether Dorner is connected to the chase. It did say that Dorner wasn't in custody, CNN's Chris Welch reported. [Updated at 4:49 p.m. ET] Two sheriff's deputies have been wounded in a shootout with a suspect believed to be renegade ex-Los Angeles police officer Christopher Jordan Dorner, a high-ranking law official with knowledge of the investigation said Tuesday. The source says the suspect, believed to be Dorner, shot the deputies as police responded to a report of a home invasion and a carjacking in the Big Bear area of southern California. After police got a description of the vehicle, police set up a road block, and Dorner approached the officers, the source says. Dorner then opened fire, wounding the two sheriff's deputies, according to the source. The official said Dorner was pinned down.  [Updated at 5:34 p.m. ET] In posts at 5:06 p.m. ET and 5:09 p.m. ET, we reported apparent information from Big Bear Lake Mayor Jay Obernolte. We have learned that the man we spoke to was not the mayor, so we’ve removed the information. We regret the error. [Updated at 5:15 p.m. ET] Former FBI Assistant Director Tom Fuentes explains to CNN what law enforcement personnel usually mean when they say someone is "pinned down": "The term commonly means he's not running any more, that they've got him trapped in a home or some other physical location ... . That means he's contained; that doesn’t mean he’s in custody ... but it means he’s not running loose." Earlier, a high-ranking law enforcement source told CNN that authorities believe they have Dorner "pinned down" in California's Big Bear Lake area after a shootout in which two sheriff's deputies were wounded Tuesday. For CNN up to date coverage please CLICK HERE  Update: 5:25 pm PST Officials awaiting the cabin to burn out and will retrieve dental records to prove identity of suspect.