Being a rich industrialist, Killian owned a foundry near London. He was well-known for putting his employees out of work, often replacing manual labor with machines and technical innovations. At some point in 1868, an incident with one of the machines resulted in an employee getting his arm mangled. Rather than offering financial compensation, Killian fired the entire crew.
When, later that year, Killian boarded the 616 train on his way to Wales for an important business meeting, he encountered one of his competitors, Angus Wolf. The two men had several drinks together, Wolf intending to get Killian so inebriated he would not be able to attend his meeting the next day. However, both men fell victim to the sleeping pills Ryan had spiked their wine with, allowing Vivian to lead Killian to her sleeping cabin.
Peter Jespers, the train's steward and a former employee of Killian, had recognized him from a picture in a newspaper, and lured Vivian away from her sleeper. Making use of Killian's drugged state, he dragged the body onto the roof of the train, and threw Killian off as the bridge crossed over a bridge, resulting in the businessman's death.