Why yes, that seems to be correct. The time of death was 9.20pm, but everyone has an alibi? Curious.
It seems you must find a person who had the means to commit a murder, while still protecting themselves with a tight alibi.
I recommend that you open your Evidence Pack and analyse it thoroughly. You can then find out what the suspects have to say about an incriminating piece of evidence by selecting it on the right.
List of Evidence