I was an ear-witness unfortunately. I heard the Captain's last exchanges with the departure director and arrival controller before JT610 went silent and the controller declared loss of radar contact.
While I see everyone commenting that the weather was VMC, if one has flown to/from Jakarta the past few months since before the Asian Games, you'd know that the conditions are hardly clear skies due to the haze.
I did remark to my FO that I suspect unreliable airspeed could be their issue and they should be climbing/holding and settle down and not come in for the approach hastily because of the visibility. This was all around 2325-2330UTC and until now I wish 2333UTC didn't occur. My thoughts and prayers to all affected.