彼がどのようにして逃げたかはいまだに謎である。の英語

How he escaped still puzzles us.

how it got out is a mystery

How and when life began is still a mystery.

The cause of his death still remains a mystery.

I don't know if I broke it in that way.

Where the treasure is hidden is still a mystery.

There are many theories about the sudden extinction of the dinosaurs, but the real cause still remains anyone's guess.

His whereabouts is [are] unknown to this day.

It hasn't been made clear how that virus entered.

However, it is not clear yet how the data was obtained.

God knows how he did it, but he did climbed that steep wall

His destination is still unknown.

after the expose he had to take it on the lam

Interestingly, the way we understand words is not always that obvious.

The whereabouts of the suspect is still unknown.

How it came about remains an unsolved question.

It is not clear how it came to Zenkoji.

The murder remains a mystery.

The cause of Tom's death is still shrouded in mystery.

His whereabouts are still unknown.

His whereabouts is as yet unknown.

He was on the verge of revealing the secret when a sharp look from Martha shut him up.

The question of how to establish the optimal formula is still open.

at such junctures he always had an impulse to leave

theories about the extinction of dinosaurs are still highly conjectural

So far we have had no news as to which route the expedition has taken.

The truth of the matter is dawning on him.

It is unclear precisely when the species lived.

Some of the victims are still unaccounted for.

It is unknown whether it was caused by espionage activities or not.