JACKSONVILLE, North Carolina (CNN) -- The remains of an adult and a fetus were found Saturday in a shallow grave in the backyard of the primary suspect in the death of a pregnant Marine, Onslow County Sheriff Ed Brown announced.

Investigators search for the body of Marine Lance Cpl. Maria Lauterbach on Saturday.

An arrest warrant has been issued for Cpl. Cesar Armando Laurean in the death of Lance Cpl. Maria Lauterbach.

He is charged with first-degree murder, although authorities have not positively identified the body as hers.

"This is consistent with what we were looking for: A pregnant lady who is the victim Maria Lauterbach and her unborn child," Brown said.

The body was charred, and the fetus was in the victim's abdomen, Brown said, describing the scene in gruesome detail.

The fetus was developed enough that the "little hand was about the size of my thumb. The little fingers were rolled up," he said.

"One of the things that will probably stick with me for a long time, and forever, is that little hand, the way those fingers were turned, that had been burned off the arm. That is bizarre. That is tragic. And it's disgusting." Watch Brown describe the scene »

The remains were taken to the Onslow County medical examiner's office. They will next be sent to the chief medical examiner in Chapel Hill, North Carolina, for DNA testing and comparison with dental records.

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Lauterbach, 20, disappeared, when she was eight months pregnant, from Camp Lejeune, North Carolina, in mid-December, not long before she was to testify at a military hearing about her rape accusation against Laurean.

Laurean is believed to have left the base at 4 a.m. Friday, and a nationwide manhunt is under way. Watch authorities search for a grave »

Lauterbach's relatives believe her pregnancy was the result of the alleged rape, said Lauterbach's uncle, Peter Steiner, a Kentucky psychiatrist.

Investigators told CNN that Laurean vanished four hours before his wife, Christina, approached Brown with a note from her husband claiming that Lauterbach had committed suicide and he buried the body.

"We believe our suspect has fled the state of North Carolina; removed himself as far from here as he can get," Brown said Saturday. Watch Brown describe the cavity where the body was found »

Brown said Friday that blood spatter evidence was found inside Laurean's home, even on a ceiling. There was evidence of "an attempted clean-up," including an attempt to paint over the blood spatter, he said.

"Evidence now is saying what he's claiming happened did not happen like he said it happened," Brown said of Laurean.

Lauterbach's mother, Mary Lauterbach, reported the young woman as missing from Camp Lejeune on December 19. Mary Lauterbach said she had not talked with her for five days. Watch police face unanswered questions »

Laurean, 21, of Nevada, is believed to be driving a black Dodge pickup with North Carolina license plate TRR1522. Laurean repeatedly refused to meet with investigators, finally telling them that his attorney wouldn't let him.

The sheriff described him as "dangerous," especially if cornered.

Military officials said Laurean was not taken into custody after Lauterbach reported the alleged rape because there was information the two carried on "some sort of friendly relationship" after she filed the complaint against him.

"The information ... leads us to believe that she still had some kind of contact" with him, said Paul Ciccarelli, agent in charge of the Naval Criminal Investigative Service at Camp Lejeune, this week.

Because of that, Laurean wasn't considered a flight risk, he said.

Steiner disputed that, and said his niece had no relationship with Laurean.

Ciccarelli also said the rape investigation is still active. See a timeline of the case »

On Friday, authorities questioned Lauterbach's roommate, Sgt. Daniel Durham, but said he had no apparent ties to her disappearance or death. Authorities have not released any details from that interview. E-mail to a friend

CNN's Ed Lavandera contributed to this report.

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