She had vanished without a trace.

她消失得无影无踪。

youdao

The youngster vanished without a trace one day and has never been found.

那个年轻人某天消失得无影无踪再也找不着了。

youdao

Youth is a brief dream, when you wake up, it had vanished without a trace.

⊙、青春时代是一个短暂的美梦，当你醒来时，它早已消逝得无影无踪。

youdao

However, Barbara Knight told the Plain Dealer newspaper she never believed she would have vanished without a trace of her own accord.

BBC: US & Canada