If you commit murder, you must go to prison.
I thought it wouldn't be fun to lead a calculating life, so I'd just do whatever I please, but I ended up becoming a murderer before I knew it.
Hey, I saw you with your girlfriend at the station yesterday. She’s so plain, she probably couldn’t even get a date with a murderer.
When you kill a person that's murder.
The readings are the kun'yomi vocab readings. So, if you know 人's reading as a vocab word and 殺す's reading, you should be able to read this word. Just note that ころし goes to ごろし due to rendaku.