Murderer
Killer
You've hopefully seen 殺人 (murder) from level 13. So, someone who does murder is what? A murderer.
さつじんしゃ
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
その殺人者は、とう走中に大変な失ぱいをおかしてしまった。
That killer made a terrible mistake while running away.
殺人者とうたがわれていましたが、ついにようぎが晴れました。
I'd been suspected of being the murderer, but I was finally cleared.
今の今まで、俺の友達の人生は信じられない苦難の連続でした。彼の人生は殺人者の子どもとして始まりました。
Up until now, my friend’s life has been an epic struggle. He began his life as the baby of a murderer.