Warning This Section Does Contain Spoilers
This is a legal complaint between the victim, Charles Macdonagh, and Susan Li, the veterinarian. Susan is taking legal action against Charles because he sent Susan the incorrect dosage for the equine (horse) patient, Captain Canter. The horse underwent surgery for colic and was given an overdose of medicine for surgery. After surgery while the horse was recovering in its stall, it drowned suddenly and unexpectedly in its water trough. Most likely the horse leaned down to get water and lost its footing, falling into the water trough and not being able to regain its footing, it drowned.