Expressions (phrases, clauses, etc.)
the trouble is ...; to make matters worse; troublingly
さらに厄介なことに、彼は近所の人に迷惑をかけていることにさえ気づいていない。To make matters worse, he isn't even conscious of annoying his neighbors.
Also written 厄介な事に【やっかいなことに】、やっかいな事に【やっかいなことに】