Andrew West, nicknamed "Westie", was a young man who worked for the government of the United Kingdom before he died from an accidental fall. He was engaged to Lucy Harrison, his girlfriend who he appears to live with.
He worked for the government, mainly on the Bruce-Partington missile project, which was a new missile defence project designed to protect the UK. We first hear about West when Mycroft Holmes arrives at 221B Baker Street and informs Sherlock Holmes that West's body was found by some railway tracks but the missile plans, which were on a memory stick, are missing. Mycroft elaborates that the flash drive contained vital information about the Bruce-Partington missile project. Sherlock however, refuses to take the case, stating that his hands are already full. He eventually asks Dr John Watson to investigate it himself.
At Sherlock's behest, John is investigating the Andrew West case on his own, and examines the crime scene, where he is puzzled to hear that little blood was found on the tracks. Sherlock appears behind him, confirming his suspicion that West was killed somewhere else and dumped on the roof of a train, and then fell off when the car experienced a slight jolt from passing over the switch points. Subsequently, they break into the apartment of West's prospective brother-in-law, Joe Harrison, who is a bike messenger. They find traces of blood on the windowsill of a window overlooking a railroad line.
When Joe comes home, they confront him about the murder and theft. Joe breaks down, confessing that he stole the Bruce-Partington data because he started dealing drugs and ended up in debt. One night he went out drinking with West, who boasted about the secret missile plans, and showed Harrison the memory stick. Harrison stole it from his drunken brother-in-law, but West realised it later and confronted him. West accidentally died in the fight when he fell down a stairway, and then Joe had the idea to place him on top of a train, to get the body as far away as possible. While a train was stopped underneath the window, Joe rolled West's body onto the train roof, and the train pulled away. The body subsequently fell off from the sudden jolt of the passenger cars when the wheel axles hit the switch points. Harrison turns over the memory stick.
- Based on the canon character of Arthur Cadogan West.