I show my sympathy for Ma Jiajue

I want to givetell you a joke. 9 Nine years ago  in China, a university student named Ma Jiajue killed four roommates. That's year, every graduates will telltold their roommates say a word,"I appreciate my roommate for not killing me or thankyou for to the roommate not killing of grace." This is a true story.

I show my sympathy for Ma Jiajue

I want to tell you a joke. 9 years ago, in China, a university student named Ma Jiajue killed four roommates. That's (maybe you mean "this year"? I can't tell) year, Every graduates will say to their roommates,"I appreciate my roommate not kill me or thanks to the roommate not kill of grace (I am not quite sure what you mean here, but it is not a sentence.)" This is a true story.

I show my sympathy for Ma Jiajue

I want to tell you a story. Nine years ago, a Chinese university student named Ma Jiajue killed four roommates. That year, every student told their roommates that they "would appreciate it if they didn't kill them" and thanked them for not doing so upon graduation. This is a true story.

i'm not sure if that was a joke or a story as I couldn't determine the punch line. Plus you finished with the statement that this is a true story.