Ever since a part from a Boeing Co. 777 was found on Reunion island last week, Grace Subithirai Nathan has been exchanging online messages through the night with loved ones of those on board Malaysian Airlines Flight 370.

"Everybody is really anxious. No one is sleeping," Nathan, whose mother was on board the plane that disappeared in March 2014, said by phone from Kuala Lumpur. "Before this, a lot of us thought it would be good to find something and have closure. But we would rather they're still alive somewhere."

The weeklong wait for testing that can determine whether the Boeing Co. 777 part came from Flight 370 is prolonging the uncertainty for friends and relatives of the disappeared. In nearly 17 months since the plane vanished with 239 people on board, no physical remnants of the aircraft have been identified.