A plunge on February 9th had left Chinese shares down by 10% on the week, their steepest fall in two years.
Some punters found solace in blaming the American embassy for the rout, which started on Wall Street.
For others it was a matter of convenience, because their real target, the Chinese securities regulator,
knew to disable comments on its Weibo account on such a grim day for stocks.
https://www.economist.com/news/finance-and-economics/21737077-american-embassy-becomes-unlikely-lightning-rod-investor-anger-chinas/

knew to という言い方はあるんでしょうか？
is(was) known to なら理解できるのですが。