VISTA, Calif. (CBS 8/CNS) - Two men accused of starting a fire last month that burned about 22 square miles over 10 days in northeastern San Diego County pleaded not guilty to arson charges Friday.

But in search warrants obtained by News 8, arson investigators claimed both defendants confessed to the crime during questioning.

Jeremy Ortiz and Jesse Durbin, both 23, were each charged with aggravated arson and arson of forest land. Superior Court Judge Marshall Hockett set bail at $2 million for both defendants, who face 10 years to life in prison if convicted.

Deputy District Attorney Terri Perez said the two set fire to a guard shack just after 10:30 p.m. on July 21 at the Eagle Rock Training Center on the edge of the Los Coyotes Indian Reservation.

The blaze spread out of control, charred 14,100 acres and left 18 firefighters with heat exhaustion, cuts, sprains, abrasions and other minor injuries. No homes were destroyed.

"Any time you set fire to a structure intentionally, burning it to the ground, it shows they are dangerous people," Perez said. She noted that the area where the fire started was especially likely to burn.

On Thursday, the California Department of Forestry and Fire Protection (Cal Fire) served four search warrants associated with the case; one on the home where Ortiz and Durbin were living on the reservation, and one on a Ford Expedition registered to Ortiz's father that was allegedly being driven by Durbin the night the fire started. The Ford is now sitting in an impound yard in Riverside County.

Two other search warrants were served to collect DNA from both suspects.

An affidavit written by Cal Fire officer James Garrett alleges Ortiz and Durbin confessed to setting the guard shack on fire using gasoline.

Officers discovered the Ford Expedition stuck in a ditch at 11:54 p.m. less than a half mile from the burning guard shack, the warrant revealed.

"Investigators discovered the hood of the vehicle was still warm and observed through open windows several items inside the vehicle, including a red plastic fuel container, a Bic lighter, and several Keystone beer cans," the search warrant said.

Investigators later found an empty can of Keystone beer near the burned out guard shack, according to the warrant.

Emergency personnel ended up evacuating Ortiz and Durbin from a house on the reservation that same night, as the wildfire advanced to within a quarter mile of the structure. Ortiz lived in the home with Durbin as his houseguest about two and a half miles from the guard shack.

The warrant said investigators recovered from the house a security surveillance camera that was identified as belonging to the Eagle Rock Training Center guard shack.

Ortiz "admitted that he poured the gasoline and that Durbin lit the gasoline," according to the warrant. "(Ortiz) also admitted that he decided to burn the shack when they were at the gate after leaving Durbin's father's house."

Ortiz "claimed that Durbin smashed the camera on the shack and subsequently carried it up to Ortiz's house," the records state.

As for Durbin, he "admitted to driving the vehicle involved and knowing Ortiz wanted to set the fire," the warrant continued. "(Durbin) said he was present when Ortiz burned the guard shack."

The privately-run Eagle Rock Training Center (ERTC) leases land from the Los Coyotes Indians and provides training facilities for the military and law enforcement.

An employee at a nearby market in Warner Springs told News 8 that Ortiz once worked at ERTC as a security guard stationed at the same shack he is now accused of burning down.

"I think he worked at the guard shack," said market clerk Shasta Fields. "I think he quit, went to do something else, and then tried to come back and they wouldn't give (his job) back to him."

ERTC Chief Executive Officer Sean Roach confirmed to News 8 that Ortiz resigned at the end of May 2011, one and a half months before the guard shack was torched.

Roach released a written statement late Friday that read in part, "Jeremy Ortiz had previously resigned his position at the ERTC… and was eligible for rehire."

Fields, the Warner Springs market clerk, said Ortiz and Durbin came inside the market and spoke with her before their arrest, the morning after the fire started.

"They weren't really suspicious. They just came in, got a couple drinks, and took off," Field said. "All (Ortiz) said was they impounded his car but he didn't know why."

Ortiz was arrested Thursday in Warner Springs, while Durbin was already in custody on an unrelated auto theft case when arson charges were filed against him.

Cal Fire authorities plan to seek substantial restitution from the defendants, if convicted. It cost about $15 million to fight the blaze.