피의자가 · 피의자를
suspect (under investigation)
Example
경찰은 피의자를 불러서 조사했어요.
The police called in the suspect for questioning.
Word parts
피 receive+의 suspicion+자 person
Literally 'person under suspicion'.
Good to know
A 피의자 becomes a 피고인 once formally indicted.