More than 500 Rohingya vanished at sea - what happened?

More than 500 Rohingya vanished at sea - what happened? Two boats carrying an estimated 530 Rohingya asylum seekers left Myanmar's Rakhine state on 29 June, and have not been heard from since. The equivalent of a jumbo jet full of people has vanished. It is very likely that they both capsized. The monsoon has started, the seas are rough, and the boats - usually old fishing trawlers converted to carry as many people as possible - are barely sea-worthy with unreliable engines.