"Vanish" is a bit of a journalistic exaggeration.

News reports are that the data links from the plane and radar give a good location where the plane went down. Radar tracked "a plane" (presumably the plane in question) "descending" at that location. The location is over the ocean, and "so far" no wreckage has been sighted. Reports are that there were no distress calls call from the aircraft, but that the data links from the aircraft have the same data that would be on the flight data recorders, so they should indicate if it was something mechanical. The data links are automatically recorded.

The are images from flightradar24 that show where the aircraft stopped transmitting, and they were shown on the news about 30 minutes ago; I don't know if these images are available on the flightradar24 website.