The remains of an American pilot who died in a plane crash in Cameroon last year are still in the cockpit even though villagers discovered the wreckage of his anti-poaching aircraft more than a month ago, officials and the pilot's family said.

The discovery of pilot Bill Fitzpatrick and his Cessna 172 in forested, mountainous terrain in April had brought some relief to his family following lengthy search efforts that began after Fitzpatrick disappeared on the night of June 22.

But Fitzpatrick's brother, Ken, said in an email to The Associated Press that the family is frustrated at the delay in recovering the pilot's remains and returning them to the United States.

"Sadly, my brother is still seated in the pilot seat in the wreckage of his plane. This is horrible!" Ken Fitzpatrick wrote.

African Parks, a Johannesburg-based group that employed Bill Fitzpatrick, cannot remove the remains on its own and is waiting for Cameroonian officials to assist, group spokeswoman Cynthia Walley said Monday. The plan is to hand over the remains to U.S. diplomats, according to Walley.

Quetong Hardison, a government official in the southwestern area of Cameroon where the plane was found, said the crash site has been secured and an investigation is underway.

"Rest assured that Bill's remains have been conserved and still sit on the pilot's seat with the clothes he was wearing," Hardison said.

Fitzpatrick's final destination was to be Odzala-Kokoua National Park in Republic of Congo, which is managed by African Parks. The job of the former Peace Corps volunteer would have been to scan the central African park's clearings for elephant carcasses from his cockpit and alert rangers who could intercept poachers escaping with ivory tusks.

There was no mayday signal on the night of 59-year-old Fitzpatrick's disappearance, suggesting he crashed into a mountain without time to react, and that weather or a fuel shortage was not the cause. No signal was detected from the plane's emergency transmitter.

Fitzpatrick's wife, Paula, and their three children live in Chelan, Washington.