Investigators searching for the missing Malaysia Airlines plane are widening their search.

The mystery surrounding the flight has deepened after an oil slick spotted in the water was ruled out of the investigation.

Friends and relatives of the 239 people on board have been told to prepare for the worst.

Juliette Gash reports;

MH-370 went missing off the coast of Vietnam.

Searches are ongoing in an area with a radius of 100km in the Gulf of Thailand between Malaysia and Vietnam.

Crews are also searching in the Andaman sea, to the west of the Malaysian peninsula.