REDDING, Calif., Aug. 7 (UPI) -- The nine people listed as missing in a California helicopter crash are almost certainly dead, a police officer said Thursday.

Eric Palmer, undersheriff of Trinity County, said investigators have found some remains around the crashed helicopter.

Contract firefighters employed by Grayback Forestry were being ferried to the Buckhorn Fire, a massive wildfire in Shasta-Trinity National Forest, when the crash occurred. The presumed dead include seven Grayback firefighters, one of the two pilots and a ninth person that Grayback said was not an employee.

Four people were rescued, including a pilot and three firefighters. Two of them remained in critical condition Thursday.

Kitty Higgins, a spokeswoman for the National Transportation Safety Board, said the helicopter had just taken off and traveled less than 500 feet when it came down. It was taking the firefighters from one base to another.

She said two men managed to get out even though their clothes were on fire. A third man escaped on his own and pulled the fourth survivor out of the wreckage.

The Grayback firefighters were all residents of Oregon.