A Spanish company, which manufactures wing parts for Boeing 777 jets, cast doubts over a flaperon’s link to the missing Malaysia Airlines Flight MH370, CNN reported Monday. The news comes as mystery over the flaperon’s discovery deepens after French authorities gave no confirmation about its origin even after concluding the first phase of inspections late last month.

The company told French investigators that it "cannot tell with certainty" if the part of a Boeing 777 wing, which was found on Réunion Island in the Indian Ocean in July, was from Flight MH370, CNN reported, citing a French source.

French investigators had hoped that serial numbers found on the flaperon could be matched with records from the Spanish company to confirm that the debris was from the missing plane, but it “proved impossible.”

Flight MH370 went missing on March 8, 2014 with 239 people on board while on its way from Kuala Lumpur to Beijing. The discovery of the flaperon gave rise to hopes that the mystery over the plane's disappearance would finally be solved. However, French authorities examining the flaperon, which is the strongest piece of evidence to surface so far, have not confirmed its origin even after a month of its discovery. Malaysian authorities previously confirmed the flaperon’s link to the missing Boeing 777-200.

"There are strong indications that this flaperon is from MH370, but we are still unsure. We are still missing identification from the parts list in order to fully confirm it is from MH370," Martine Del Bono from French aviation body Bureau d'Enquêtes et d'Analyses (BEA) told CNN.

Despite more than a year of searches, no significant clues have been found in the ongoing investigation into the disappearance of the plane. An international search, led by Australia, is underway in an area of 46,332 square miles in the southern Indian Ocean, where authorities believe the plane went down.

Last week, experts in Germany raised doubts over the current search area, saying it is thousands of miles off-target.

Malaysia, Australia and China are expected to meet this month to determine whether the search area should be narrowed down.