The confirmation by Malaysia that the piece of a plane's wing found washed up on the French island of Reunion belongs to missing Malaysia Airlines Flight MH370 is but a small part of the mystery. It would seem to prove correct the theory of investigators that the Boeing 777 on a flight from Kuala Lumpur to Beijing veered off course and crashed into the southern Indian Ocean. But the find does not bring closure for the mostly Chinese relatives of the 239 people on board, nor does it answer the vital questions of what happened to the jet and where its fuselage and data and voice recorders, key pieces of equipment that could provide the answers, lie. Only a continued, well-funded, investigation gives that hope.

Trust in Malaysian Prime Minister Najib Razak's announcement is one matter; relatives have lost faith in the country's authorities. The initial search after the plane disappeared on March 8 last year was in the wrong area, crucial data from military radar was not released for days and information from officials was sometimes distorted. Reason for caution lies in French investigators stopping short of backing the confirmation, instead saying there was a "very strong presumption" that the debris belonged to MH370, although more study was needed before there could be conclusive proof. The Chinese Foreign Ministry is therefore right to urge Malaysia to continue to look into the cause of the tragedy and "protect the rights and interests of the families involved".

Before the discovery, there had been talk of scaling back the search. Criticism of the expense and duration had been growing, particularly in Australia, which is leading the mission and shouldering the cost with Malaysia. But never in aviation history has there been so extensive a recovery effort: So far, 55,000 sq km of ocean floor have been searched and the final area could be 120,000 sq km. The Reunion finding has sparked renewed effort and France has sent search teams to the island.