Web extra: How authorities identify a burned body

(CNN) -- A charred body, such as that found in a California cabin amid a manhunt for an ex-police officer, can be relatively easy to identify, experts said, especially if authorities have an idea of whose it is.

Officials are working to determine whether the body, discovered after a shootout that left one deputy dead and a second wounded, is that of Christopher Dorner.

Suspected in the deaths of three others, Dorner, a former Los Angeles police officer, has been the subject of a six-day manhunt. He apparently vowed to kill police officers to avenge what he said was an unfair termination.

"We do cases like this all the time," said Dr. Mark Bernstein, a Louisville, Kentucky, dentist who is a forensic dental consultant for the state's chief medical examiner.

Frequently, when a body has been burned, fingerprints are not a viable option for identification, as the skin has burned, he said. But it's rare, even in the most severe burning, that "some fragments of dental evidence" wouldn't exist.

Typically, medical examiners or other forensic experts would start with a person's family, asking relatives if they know the person's dentist, Bernstein said.

If a dentist remains unknown, other sources for dental X-rays can be checked. Those might include the military, if a person was in the armed forces, or even jail, where an inmate might have been treated for a dental condition.

Dorner, for instance, retired from the Navy Reserve on February 1 as a lieutenant.

Although Bernstein is not involved in the Dorner case, "I think that all the elements are there for a possible identification," he said. "Dental identifications are so much quicker and so much less expensive than DNA."

If dental records cannot be found, authorities can also check with hospitals for any other X-rays that might have been taken, said Dr. Daniel Spitz, medical examiner in Macomb County, Michigan. Chest or orthopedic X-rays can be particularly useful for comparisons, he said.

If no X-rays can be found, experts said the next step would be DNA testing. In spite of the fire damage, there are a number of ways DNA can be located on a body, Bernstein and Spitz said.

"The charring is only on the surface," unless an accelerant was used or unless the body was subjected to "crematory-like temperatures," causing it to disintegrate, Spitz said.

DNA can be extracted from the center of a tooth or from bone marrow, Bernstein said.

In addition, "the skull almost always stays, for the most part, intact, leaving the brain in relatively good shape," Spitz said. Internal organs sometimes are also present, and blood can be drawn from them.

If a person's DNA is not found in national DNA databases, a source for comparison must be found, he said. Authorities may obtain a sample from a person's toothbrush or hairbrush, for instance, and tests may also be done comparing blood samples from family members, although those are more labor-intensive and time-consuming.

But in most cases, dental records are all that's needed, Bernstein said. "It's typical that we can do that."

In this case, he said, "They're going to do everything they can to identify this individual. It's critical."