SAN DIEGO -- Investigators looking for the source of the Cedar fire found "an unnaturally piled bundle of sticks and grasses," indicating a lost novice hunter set the blaze in order to be found, according to court papers.

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In recently filed court documents, federal prosecutors detail what led them to charge Sergio Martinez, 34, of West Covina with setting the largest wildfire in California history and lying about it, The San Diego Union-Tribune reported Thursday.

In court papers, Assistant U.S. Attorney Kevin Mulcahy gave the most detailed account to date of what prosecutors believe led to the blaze, the Union-Tribune reported.

He said that when investigators went to the area where the fire was first reported they examined burned trees, bushes and grasses left behind and pieced together the path of the fire.

That led them to the fire's origin, in the Kessler Flats area four miles southwest of Pine Hills, where they found a bundle of sticks and grasses "next to a plant that had been twisted and had its stems pulled off," Mulcahy said, according to the Union-Tribune.

"Martinez claimed on the night of the fire that a bullet probably caused the blaze," Mulcahy wrote in the court filing, according to the newspaper. But he added that there was no evidence to support the claim.

"There were no damaged rocks, no shell casings and no bullets at the scene. Instead, the investigation showed a manmade gathering of fuels at the precise point of origin of the Cedar Fire," Mulcahy said.

The fire eventually burned 270,000 acres, destroyed more than 2,200 homes and killed 15 people.

Defense lawyers have asked that the trial be moved out of San Diego or delayed, contending Martinez could not get a fair trial in the county.