This is all just part of normal gameplay, but if anyone is stuck on recreating the timeline, here it is...
4.30 AM - Time of Death by the doctors.
4.45 AM - Richardson arrives at house.
4.50 AM - Richardson leaves house.
5.20 AM - Cadoch loiters in garden.
5.24 AM - Cadoch hears a noise in the garden.
5.30 AM - Long sees a man and woman speaking.
5.32 AM - Cadoch leaves for work.
6.20 AM - Holmes and Watson arrive.
Then, you will have to make corrections due to variables, such as all the clocks in town being set wrong, here are the changes:
5.28 AM - Long sees a man and woman speaking.
5.29 AM - Cadoch loiters in garden.
5.30 AM - The murder takes place.
5.31 AM - Cadoch leaves for work.