I re-read the chapter and logically, killing shuli does not make sense at all... I do understand why the author would do it, in terms of plot, but let's see, she is a noble, from one of the most important families of the country, OF COURSE it would be investigated, she was brutally murdered, why would you kill a noble? You could get a ransom with her... It screams death by order, any stupid person would be aware of it