They are going to have to conduct and expanding search pattern out to about 2,500nm from KL in ALL directions......
Also get ALL Radar centers in that search area I describe ( both civil and Military ) to check their recorded displays for any strange targets flying through their airspace on that morning......
Big job.
Like I said pages back, you do realise this 777 may be at the bottom of the Indian Ocean 2,500 nm west of Indonesia...