At 0617 Pacific time, a Cessna 182Q suffered an in-flight loss of control shortly after takeoff from runway 36 at Lake Tahoe Airport. The flight instructor received minor injuries. The pilot and one passenger were not injured. The Civil Air Patrol pilot told investigators they were activated for a mission to search for a missing aircraft. They were repositioning to WMC, where the search was being coordinated. Shortly after takeoff, the nose pitched up despite the pilots attempts to flatten the aircrafts attitude. The CFI took control, but the pitch controls appeared to be jammed. The rear seat passenger moved forward to see if weight distribution would help. The pilot and instructor were both applying forward pressure on the yoke. They retarded the throttle, and the airplane descended into bushes and nosed over. Inspection of the wreckage showed the elevator down cable turnbuckle safety wire was cut, and the cable was out of the turnbuckle and lying on floor of the empennage. The elevator up cable turnbuckle safety wire was also cut; however, it was still attached to the turnbuckle.