Cameroon has opened an inquiry into the crash of a Kenya Airways plane that killed all 114 people on board Saturday.

Officials Tuesday say the investigation is focusing on why the plane went down and the delay in finding the wreckage.

The crash site was found in a mangrove swamp about 20 kilometers from Douala airport after nearly two days of searching.

Initially, the search focused on an area at least 140 kilometers from Douala based on information received from a satellite signal.

The U.S. National Transportation Safety Board has sent a team to assist the Cameroon government in its investigation.

On Monday, recovery teams found one of two "black boxes" belonging to the aircraft. However, they were unable to specify whether it was the flight data recorder or the cockpit voice recorder.

The plane had taken off from Douala en route to the Kenyan capital, Nairobi.

Some information for this report was provided by AP and Reuters.