'Located' would mean visually identified on the bottom of the Ocean.
Clearly this can't be the case.
Why not? If Echo has been able to do scan of a particular area and it is showing clear signs of the wreckage, that would be reasonable to be confident.
When South African Airlines lost a 747 in 1987, after two months of searching for the recorder pingers, a deep sea sonar scan gave them a definite crash site within two days of searching.
If they can find wreckage at 4900m in two days, why is anyone surprised they can do the same more than twenty years later? With MH370 they have pretty much followed the same techniques